The Best Medicine cast is led by Josh Charles as Dr. Martin Best, with Abigail Spencer as Louisa Gavin, Annie Potts as Aunt Sarah, Josh Segarra as Sheriff Mark Mylow, and Cree as Elaine Denton. The FOX medical comedy premiered in January 2026 and quickly earned a second season, which is scheduled to begin on September 22, 2026.
The series is the American adaptation of the much-loved British comedy-drama Doc Martin. But instead of simply copying the original, Best Medicine moves the story to a small fishing village in Maine and gives the characters new names, relationships, and American personalities. You can find the current series information on FOX’s official Best Medicine page.
So who plays Dr. Martin Best? Who is Louisa? Why is Annie Potts in the show? And which original Doc Martin star surprisingly appears in the American remake?
Here is the full, easy-to-understand guide.
Best Medicine Cast Quick List
| Actor | Character |
|---|---|
| Josh Charles | Dr. Martin Best |
| Abigail Spencer | Louisa Gavin |
| Josh Segarra | Sheriff Mark Mylow |
| Cree | Elaine Denton |
| Annie Potts | Aunt Sarah |
| Stephen Spinella | Greg Garrison |
| Jason Veasey | George Brady |
| Carter Shimp | Al Large |
| John DiMaggio | Bert Large |
| Clea Lewis | Sally Mylow |
| Didi Conn | Geneva Potter |
| Martin Clunes | Dr. Robert Best |
| Wattson | Copernicus the dog |
FOX identifies Josh Charles, Abigail Spencer, Josh Segarra, Annie Potts, and Cree as the show’s central stars. It also lists Stephen Spinella, Jason Veasey, Didi Conn, Clea Lewis, John DiMaggio, Carter Shimp, and Martin Clunes among the recurring cast.
What Is Best Medicine About?
Best Medicine follows Dr. Martin Best, a brilliant surgeon from Boston who suddenly leaves his successful career and moves to Port Wenn, a small fishing village in Maine.
Why would a top surgeon do that?
Martin spent childhood summers there, so the town has personal meaning.
There is another problem too.
Martin has developed a serious phobia connected with blood, something that makes his career as a surgeon much more complicated. Instead of staying in Boston, he becomes the local general practitioner in Port Wenn.
Unfortunately, Martin is excellent at medicine and terrible at talking to people.
He is blunt.
He can sound rude.
He hates unnecessary conversation.
And the people of Port Wenn seem to love unnecessary conversation.
That clash creates much of the comedy.
Josh Charles as Dr. Martin Best
Josh Charles plays the main character, Dr. Martin Best.
Charles is already well known to television audiences, especially for playing Will Gardner in The Good Wife. That performance earned him two Emmy nominations and a Golden Globe nomination.
In Best Medicine, his character is almost the opposite of the warm family doctor you might expect.
Martin can diagnose difficult medical conditions.
But ask him to comfort someone?
That is where things become awkward.
His bedside manner can be so direct that patients sometimes feel worse after speaking to him.
Still, Martin is not simply rude for fun.
FOX explains that his behavior hides psychological problems, personal trauma, and his difficulty forming close relationships.
That makes him more than a comedy character.
He is funny because of the situations he creates, but there is pain underneath.
Josh Charles Was the First Major Star Announced
FOX announced Best Medicine in May 2025 with Josh Charles already attached as the lead.
The network gave the show a straight-to-series order rather than making only a pilot and waiting to decide later.
That was a strong sign of confidence.
And casting Charles made sense.
He has experience with drama.
He can handle dry comedy.
And he knows how to play complicated characters who may behave badly while still keeping the audience interested.
Martin Best needs exactly that balance.
Abigail Spencer as Louisa Gavin
Abigail Spencer plays Louisa Gavin, the local schoolteacher.
Louisa quickly becomes one of the most important people in Martin’s life.
She is warmer than he is.
She understands people better.
And she is not impressed simply because Martin is a talented doctor.
That creates an interesting relationship.
Martin is used to being the smartest person in the room.
Louisa does not care.
If he is being rude, she tells him.
If he makes a mistake, she notices.
And despite all their differences, there is obvious romantic tension between them.
Where Have You Seen Abigail Spencer Before?
Abigail Spencer has had a long television career.
Many viewers know her from shows such as Suits, Timeless, Rectify, and Grey’s Anatomy.
Her experience fits Louisa well because the character needs both warmth and strength.
Louisa cannot simply stand beside Martin and agree with everything he says.
She needs enough personality to challenge him.
That becomes increasingly important as the story moves into its second season.
Josh Segarra as Sheriff Mark Mylow
Josh Segarra plays Sheriff Mark Mylow.
Mark is Port Wenn’s sheriff and one of the town’s more energetic personalities.
Compared with Martin, Mark is much more comfortable around people.
He talks.
He jokes.
He gets involved in local problems.
And his personality often makes Martin’s quiet, irritated behavior look even funnier.
Segarra has appeared in many television series, including Arrow, The Other Two, Sirens, and Abbott Elementary.
FOX lists him as one of the five main stars of Best Medicine.
Sheriff Mark Is More Than Comic Relief
At first, Mark can seem like one of the funny locals who exist mainly to annoy Martin.
But the character gradually becomes more important.
He has his own relationships.
He is connected deeply with the town.
And by the end of the first season, his personal history begins affecting the romantic situation around Louisa and Martin.
That becomes especially important for Season 2.
Current previews say the new season will explore a complicated romantic triangle involving Louisa and someone from her past.
Annie Potts as Aunt Sarah
One of the most recognizable members of the Best Medicine cast is Annie Potts.
She plays Aunt Sarah.
Potts has been acting for decades and is known from films and shows including Ghostbusters, Designing Women, Pretty in Pink, and Young Sheldon.
For many viewers, seeing her in this small Maine town is one of the show’s biggest attractions.
Aunt Sarah has an important family connection with Martin.
She understands parts of his past that the rest of Port Wenn does not.
That means she can sometimes see through his cold behavior.
Why Aunt Sarah Matters to Martin
Martin may want everyone to leave him alone.
Aunt Sarah does not accept that very easily.
Family gives her permission to push past the walls he builds around himself.
She knows where he came from.
She understands his childhood.
And she can sometimes explain things about Martin that he would never explain himself.
That gives Annie Potts a role that mixes comedy with emotional moments.
FOX continues to list Aunt Sarah as one of the central characters heading into Season 2.
Cree as Elaine Denton
Cree plays Elaine Denton.
Elaine works around Martin’s medical practice and becomes another person who constantly tests his patience.
She is younger, confident, and brings a completely different energy into the clinic.
Martin wants efficiency.
Elaine has her own way of doing things.
You can probably guess how well that goes.
Cree is part of the official main cast alongside Charles, Spencer, Segarra, and Potts.
Her character helps make the medical office feel less like a serious hospital drama and more like a workplace comedy where personalities keep colliding.
Stephen Spinella as Greg Garrison
Stephen Spinella plays Greg Garrison.
Greg is one of the owners of The Salty Breeze, a local business in Port Wenn.
His husband is George Brady.
The pair quickly became memorable supporting characters during the first season.
FOX initially described Spinella and Jason Veasey as recurring guest stars.
But their roles became popular enough that something changed for Season 2.
Jason Veasey as George Brady
Jason Veasey plays George Brady, Greg’s husband and fellow proprietor of The Salty Breeze.
Together, George and Greg help give Port Wenn the feeling of a real community.
They are not simply random patients appearing for one episode.
They are people Martin continues seeing.
They know everybody.
They hear the gossip.
And, like almost everyone in town, they can become part of Martin’s problems whether he wants them to or not.
PEOPLE reports that Stephen Spinella and Jason Veasey have been promoted to series regulars for Season 2.
That means viewers should expect much more from Greg and George.
Carter Shimp as Al Large
Carter Shimp plays Al Large.
Al is the son of Bert Large and another familiar member of the village.
The surname may already sound familiar to Doc Martin fans.
That is because the American adaptation keeps several ideas and character relationships from the original British series while changing the actors and setting.
IMDb currently lists Shimp across multiple Season 1 episodes.
John DiMaggio as Bert Large
John DiMaggio plays Bert Large.
Yes, this is the same John DiMaggio famous for voice acting.
He is the voice of characters such as Bender in Futurama and Jake the Dog in Adventure Time.
In Best Medicine, however, audiences actually see him on screen.
Bert is a handyman and one of Port Wenn’s colorful residents. FOX lists DiMaggio among the show’s recurring cast.
It is a fun change for viewers who mainly recognize his voice.
Clea Lewis as Sally Mylow
Clea Lewis plays Sally Mylow, the local pharmacist.
She is also connected to Sheriff Mark Mylow.
A pharmacist naturally becomes important in a small-town medical show because Martin regularly sends patients for medication.
But in Port Wenn, nothing remains purely professional for very long.
Everyone knows everyone.
Family relationships overlap with work.
And a medical problem can quickly turn into town gossip.
FOX lists Clea Lewis as a recurring performer.
Didi Conn as Geneva Potter
Didi Conn plays Geneva Potter, a local councilwoman.
Fans of classic movies may recognize Conn immediately.
She famously played Frenchy in Grease.
Her appearance gives Best Medicine another experienced comedy performer.
Geneva helps represent the local government and the many small-town personalities Martin has to deal with.
For a man who wants privacy, moving into a village where everyone knows his business may have been the worst possible choice.
That is also why the show works.
The Most Surprising Cast Member: Martin Clunes
Here is where Best Medicine gets especially clever.
Martin Clunes, the actor who played Dr. Martin Ellingham in the original British series Doc Martin, appears in the American remake.
But he does not play the American version of Doc Martin.
Josh Charles already has that job.
Instead, Clunes plays Dr. Robert Best—Martin Best’s father.
That creates a funny connection between the two shows.
The original Doc Martin actor is now literally the father of the new American doctor.
It is almost like the British series passing the character to the next generation.
Martin Clunes Is Returning in Season 2
Clunes appeared during Season 1 in the episode appropriately titled “Doc Martin.”
His appearance was not just a tiny joke.
Robert Best has a difficult relationship with his son.
Their family history includes painful events, including the death of Martin’s sister Rosemary.
And FOX is not finished with the character.
Martin Clunes is officially returning during Season 2.
That gives longtime Doc Martin viewers another reason to watch the American adaptation.
Copernicus the Dog
Not every memorable cast member is human.
A dog named Wattson plays the stray dog Copernicus.
FOX describes Copernicus as lovable, while Josh Segarra jokingly called Wattson the best actor on the set.
Animals often become fan favorites in small-town shows.
Copernicus fits perfectly.
Martin may not want another emotional connection in his life.
But Port Wenn keeps giving him people—and animals—to care about.
Is Best Medicine a Remake of Doc Martin?
Yes.
Best Medicine is officially based on the British television series Doc Martin.
The original starred Martin Clunes as Dr. Martin Ellingham and became a long-running international success.
FOX Entertainment Studios produces the American adaptation, with Liz Tuccillo developing it for American television.
The basic idea remains familiar.
A talented but difficult doctor.
A small coastal town.
A romantic relationship with a teacher.
Strange patients.
Colorful neighbors.
But the new show changes the setting from Cornwall in England to Maine in the United States.
How Many Episodes Are in Best Medicine Season 1?
Season 1 has 13 episodes.
FOX’s streaming page lists the premiere, “Docked,” on January 4, 2026 and the thirteenth episode, “Norway No How,” on April 7.
That gave viewers enough time to get familiar with Port Wenn before the season-ending cliffhangers.
And FOX did not wait long to make a decision about the show’s future.
Was Best Medicine Renewed?
Yes.
FOX renewed Best Medicine for Season 2 in March 2026.
The second season premieres on Tuesday, September 22, 2026.
That means as of September 11, 2026, fans have less than two weeks to wait.
Season 2 will continue Martin’s medical problems, relationships, and difficulties with the people of Port Wenn.
And the cast is growing rather than shrinking.
Who Is Returning for Best Medicine Season 2?
The core five are returning:
Josh Charles as Martin Best.
Abigail Spencer as Louisa Gavin.
Josh Segarra as Mark Mylow.
Annie Potts as Aunt Sarah.
Cree as Elaine Denton.
Stephen Spinella and Jason Veasey are also moving up to regular status.
Martin Clunes will return as Dr. Robert Best.
That gives Season 2 a strong combination of original stars and expanded supporting characters.
Why the Best Medicine Cast Works
The show would not work if Martin were the only interesting character.
The entire joke depends on contrast.
Martin wants quiet.
The town wants conversation.
Martin wants facts.
The town wants feelings.
Martin wants everyone to behave logically.
Port Wenn appears determined to do the opposite.
Abigail Spencer gives him a romantic challenge.
Josh Segarra gives the town energy.
Annie Potts brings family history.
Cree adds chaos inside the clinic.
And characters such as Greg, George, Bert, Sally, and Geneva make the town feel alive.
That is why the ensemble matters as much as the doctor.
Final Thoughts
The Best Medicine cast combines familiar television stars, experienced comedy performers, and one especially clever connection with the original Doc Martin.
Josh Charles leads the series as Dr. Martin Best, a brilliant former Boston surgeon whose medical ability is far better than his people skills. Abigail Spencer plays Louisa Gavin, the schoolteacher who refuses to be intimidated by him. Josh Segarra brings charm and humor as Sheriff Mark Mylow, while Annie Potts plays Martin’s Aunt Sarah and Cree plays Elaine Denton.
The supporting cast makes Port Wenn feel like a real little town.
Stephen Spinella and Jason Veasey play Greg and George.
John DiMaggio becomes handyman Bert Large.
Carter Shimp plays Al Large.
Clea Lewis is pharmacist Sally Mylow.
Didi Conn appears as councilwoman Geneva Potter.
And Wattson plays Copernicus, the dog who may secretly be stealing the whole show.
Then there is Martin Clunes.
The actor who spent years playing the original British Doc Martin now appears as the father of Josh Charles’ American doctor.
That is the kind of casting joke longtime fans can appreciate even if new viewers know nothing about the original series.
Most importantly, this cast is not finished.
Season 1 ended in April 2026.
FOX renewed the series.
And Best Medicine Season 2 premieres September 22, 2026.
The doctor is coming back.
Unfortunately for Martin Best, so is everybody else in Port Wenn.
Frequently Asked Questions About the Best Medicine Cast
Who plays Dr. Martin Best in Best Medicine?
Josh Charles plays Dr. Martin Best, the brilliant Boston surgeon who becomes a small-town doctor in Port Wenn, Maine.
Who plays Louisa in Best Medicine?
Abigail Spencer plays schoolteacher Louisa Gavin.
Who plays Sheriff Mark Mylow?
Josh Segarra plays Sheriff Mark Mylow.
Who plays Aunt Sarah?
Annie Potts plays Martin’s Aunt Sarah.
Who plays Elaine Denton?
Cree plays Elaine Denton, who works around Martin’s medical practice.
Who plays Greg and George?
Stephen Spinella plays Greg Garrison, while Jason Veasey plays George Brady. Both have been promoted to series regulars for Season 2.
Is Martin Clunes in Best Medicine?
Yes. The original Doc Martin star appears as Dr. Robert Best, the father of Josh Charles’ character.
Is Martin Clunes returning for Season 2?
Yes. He is returning as Robert Best in the second season.
Who plays Bert Large?
John DiMaggio plays Bert Large.
Who plays Al Large?
Carter Shimp plays Al Large.
Who plays Geneva in Best Medicine?
Grease star Didi Conn plays councilwoman Geneva Potter.
Who plays Sally Mylow?
Clea Lewis plays pharmacist Sally Mylow.
Is Best Medicine based on Doc Martin?
Yes. It is the American adaptation of the British hit Doc Martin.
How many episodes are in Best Medicine Season 1?
Season 1 contains 13 episodes.
When did Best Medicine premiere?
The series premiered on FOX on January 4, 2026.
Is Best Medicine getting Season 2?
Yes. FOX renewed the series, and Season 2 premieres on September 22, 2026.
Where can you watch Best Medicine?
FOX carries the series, with streaming availability also including Hulu and Disney+ in supported markets. Season 1 has additionally become available on Netflix in the United States.
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