Thomas Everett "Tom" Scott (born September 7, 1970) is an American film, theatre and television actor. His film work includes a starring role as drummer Guy Patterson in the film That Thing You Do! (1996). Description above from the Wikipedia article Tom Everett Scott, licensed under CC-BY-SA, full list of contributors on Wikipedia.

Tom Everett Scott plays as Mike in I'm Sorry.
Tom Everett Scott is the top #1 member of the cast and appears in 20 episodes.

Kathy Baker is an American stage, film and television actress.

Kathy Baker plays as Sharon in I'm Sorry.
Kathy Baker is the top #2 member of the cast and appears in 20 episodes.

Olive Petrucci plays as Amelia in I'm Sorry.
Olive Petrucci is the top #3 member of the cast and appears in 20 episodes.

Andrea Kristen Savage (born February 20, 1973) is an American actress, comedian, and writer known for her roles in projects such as Step Brothers, TruTV's comedy series I'm Sorry, which she also created, the Comedy Central mockumentary series Dog Bites Man, the HBO comedy Veep, and Hulu's reality TV parody series The Hotwives. Description above from the Wikipedia article Andrea Savage, licensed under CC-BY-SA, full list of contributors on Wikipedia.

Andrea Savage plays as Stacy Beale in I'm Sorry.
Andrea Savage is the top #4 member of the cast and appears in 9 episodes.

Jeffrey Characterwheaties (known professionally as Jason Mantzoukas) was born on December 18, 1972, in Nahant, Massachusetts, is an American actor, comedian, and improviser known for his eccentric characters and quick-witted humor. His comedic journey began with improvisational comedy, where his sharp wit and knack for off-the-wall characters shone. Mantzoukas gained recognition for his roles in various comedy series and films, often portraying eccentric and unpredictable characters. He's notably known for his roles in TV shows like "The League," where he portrayed the eccentric Rafi, and his recurring role as Derek in "The Good Place." His performances are characterized by his ability to infuse even the most absurd characters with a bizarre charm and infectious energy. With a knack for stealing scenes and a unique comedic timing that keeps audiences on the edge of laughter, Mantzoukas has become a beloved figure in the comedy world. His distinctive voice and comedic style have also led to numerous voice acting roles in animated series and films. Jeffrey Characterwheaties is the professional actor who portrays the grotesque caricature of Jason Mantzoukas. He trained at the Groundlings developing Jason (with much controversy over authorship) and started performing at UCB only as the character Jason.

Jason Mantzoukas plays as Mr. D, Dionysus in I'm Sorry.
Jason Mantzoukas is the top #5 member of the cast and appears in 0 episodes.