John Mahoney was a British actor, best known for playing Martin 'Marty' Crane, the retired police officer, father of Kelsey Grammer's Dr. Frasier Crane, in the American sitcom "Frasier" (NBC, 1993–2004).

John Mahoney plays as Martin Crane in In Treatment.
John Mahoney is the top #1 member of the cast and appears in 264 episodes.

Gabriel James Byrne (born 12 May 1950) is an Irish actor, film director, film producer, screenwriter, cultural ambassador and audiobook narrator. His acting career began in the Focus Theatre before he joined London’s Royal Court Theatre in 1979. Byrne's screen début came in the Irish soap opera The Riordans and the spin-off show Bracken. The actor has now starred in over 35 feature films, such as The Usual Suspects, Miller's Crossing and Stigmata, in addition to writing two. Byrne's producing credits include the Academy Award-nominated In the Name of the Father. Currently, he is receiving much critical acclaim for his role as Dr. Paul Weston in the HBO drama In Treatment.

Gabriel Byrne plays as Paul Weston in In Treatment.
Gabriel Byrne is the top #2 member of the cast and appears in 106 episodes.

Dianne Evelyn Wiest (born March 28, 1946) is an American actress. She has won two Academy Awards, two Emmy Awards and a Golden Globe Award, and has also been nominated for a BAFTA Award.

Dianne Wiest plays as Nora Lewin in In Treatment.
Dianne Wiest is the top #3 member of the cast and appears in 48 episodes.

Blair Underwood (born August 25, 1964) is an American television and film actor. He is perhaps best known as headstrong attorney Jonathan Rollins from the NBC legal drama L.A. Law, a role he portrayed for seven years. He has gained critical acclaim throughout his career, receiving numerous Golden Globe Award nominations, three NAACP Image Awards and 1 Grammy Award. In recent years, he has appeared on The New Adventures of Old Christine, Dirty Sexy Money and In Treatment and currently stars in NBC's The Event. Underwood's feature film debut was the 1985 movie Krush Groove. His 1985 appearance on The Cosby Show landed him a short stint on the ABC soap opera One Life to Live, which eventually led to his performance on the TV series L.A. Law, where he appeared from 1987 to 1994. In 1996 Underwood was featured in the July issue of Playgirl. Underwood broke into film with roles in Just Cause (1995), Set It Off (1996) and Deep Impact (1998). He also had a supporting role as a geneticist in Gattaca. In 2000, he played the lead role in the short-lived television series City of Angels. In 2003, he guest starred in four episodes on the HBO series Sex and the City playing Cynthia Nixon's love interest. In 2004, he played the role of Roger De Souza opposite Heather Locklear in NBC's LAX. He gained acclaim as the sexy grade school teacher in the CBS sitcom The New Adventures of Old Christine opposite Julia Louis-Dreyfus for two years. In 2007, he guest starred in an episode of the NBC series Law & Order: Special Victims Unit. His also had a role as recurring character Alex in the HBO series In Treatment. Also in In 2007, Underwood co-authored the novel Casanegra: A Tennyson Hardwick Novel with husband-and-wife team Steven Barnes and Tananarive Due. Next, Underwood can seen as the President of the United States in the NBC drama series The Event. Underwood has received three NAACP Image Awards, for his film work in Rules of Engagement, and his television work in L.A. Law, City of Angels, Murder in Mississippi and Mama Flora's Family. He was voted one of People's "50 Most Beautiful People" in 2000, and one of TV Guide's "Most Influential Faces of the 90s". In 1989, Underwood co-founded Artists for a New South Africa, a non-profit organization dedicated to democracy and equality in South Africa. Underwood is a part of several charitable organizations. He won the 1993 Humanitarian Award for his work with the Los Angeles chapter of the Muscular Dystrophy Association. In 2003, along with Ashley Judd, he served as the spokesperson for YouthAIDS. Underwood also appeared in a 2004 public service announcement for The Fulfillment Fund. He is a Trustee for the Robey Theatre Company in Los Angeles, a non-profit theatre group founded by Danny Glover, focusing on plays about the Black experience. On September 17, 1994, he married Desiree DaCosta, with whom he has three children.

Blair Underwood plays as Alex Prince in In Treatment.
Blair Underwood is the top #4 member of the cast and appears in 43 episodes.

Embeth Jean Davidtz (born August 11, 1965) is an American-born South African actress. Description above from the Wikipedia article Embeth Davidtz, licensed under CC-BY-SA, full list of contributors on Wikipedia

Embeth Davidtz plays as Amy in In Treatment.
Embeth Davidtz is the top #5 member of the cast and appears in 43 episodes.

Josh Charles is an American stage, film and television actor. He is best known for the roles of Daniel "Dan" Rydell on "Sports Night" and as Will Gardner on "The Good Wife".

Josh Charles plays as Jake in In Treatment.
Josh Charles is the top #6 member of the cast and appears in 43 episodes.

Michelle Forbes is an American film and television actress, best known for many recurring appearances on genre and drama television shows such as "Star Trek: The Next Generation", "Battlestar Galactica", "24", "Prison Break", and "True Blood".

Michelle Forbes plays as Kate in In Treatment.
Michelle Forbes is the top #7 member of the cast and appears in 43 episodes.

Mia Wasikowska (born 25 October 1989) is an Australian actress. After starting her career in Australian television and film, she first became known to a wider audience following her critically acclaimed work on the HBO television series In Treatment. She gained worldwide prominence in 2010 after starring as Alice in Tim Burton's feature film Alice in Wonderland and appearing in The Kids Are All Right, for which she received the Hollywood Awards' Breakthrough Actress Award. In 2011, Wasikowska portrayed the title character in Cary Fukunaga's adaptation of Jane Eyre. She will also star in Gus Van Sant's Restless and Rodrigo Garcia's Albert Nobbs, in addition to shooting three additional projects by John Hillcoat, Robert Connolly and Park Chan-wook during the course of the year. That same year, she was named to the Time 100, a list of the most influential people in the world, for the first time.

Mia Wasikowska plays as Sophie in In Treatment.
Mia Wasikowska is the top #8 member of the cast and appears in 43 episodes.

Aaron Grady Shaw plays as Oliver in In Treatment.
Aaron Grady Shaw is the top #9 member of the cast and appears in 35 episodes.

From Wikipedia, the free encyclopedia. Sherri M. Saum (born on October 1, 1974 in Dayton, Ohio) is an American actress. Description above from the Wikipedia article Sherri Saum, licensed under CC-BY-SA, full list of contributors on Wikipedia.

Sherri Saum plays as Bess in In Treatment.
Sherri Saum is the top #10 member of the cast and appears in 35 episodes.