Paul Edward Valentine Giamatti ( JEE-ə-MAH-tee; born June 6, 1967) is an American actor. Giamatti's breakout film role was in Private Parts (1997), followed by supporting roles in Saving Private Ryan (1998), Man on the Moon (1999), Big Momma's House (2000), Storytelling (2001), and Planet of the Apes (2001).
He won wide acclaim for his lead roles in American Splendor (2003) and Sideways (2004), earning numerous accolades for both, including winning a Golden Globe Award for the latter. Giammati would go on to earn Academy Award nominations for Best Supporting Actor for his portrayal of Joe Gould in Cinderella Man (2005), and Best Actor for playing a disgruntled teacher in The Holdovers (2023). He has also acted in The Illusionist (2006), Shoot 'Em Up (2007), Fred Claus (2007), Barney's Version (2010), Win Win (2011), The Ides of March (2011), Cosmopolis (2012), 12 Years a Slave (2013), Saving Mr. Banks (2013), Love & Mercy (2014), Straight Outta Compton (2015), and Private Life (2018).
On television, Giamatti played the title role in the HBO miniseries John Adams (2008), which earned him acclaim and several awards including a Primetime Emmy and Golden Globe. He starred as U.S. Attorney Chuck Rhoades Jr. in the Showtime series Billions (2016–2023), and earned Emmy nominations for his roles as Ben Bernanke in the HBO film Too Big to Fail (2011) and Harold Levinson in the ITV series Downton Abbey (2013). He also played Nus Braka, a part-Klingon, part-Tellarite villain in the Paramount+ series Star Trek: Starfleet Academy (2026–present).
His notable theatre work include his Broadway debut portraying Ezra Chater in the Tom Stoppard play Arcadia (1995), Rev. Donald "Streaky" Bacon in the David Hare play Racing Demon (1995), and revivals of Anton Chekhov's Three Sisters (1997) and Eugene O'Neill's The Iceman Cometh (1999).
Paul Edward Valentine Giamatti was born June 6, 1967, in New Haven, Connecticut, the youngest of three children. His father, Angelo Bartlett Giamatti, was a Yale University professor who later became president of the university and later commissioner of Major League Baseball. His mother, Toni Marilyn Giamatti (née Smith), was a homemaker and English teacher who taught at the Hopkins School and had also previously acted.
His paternal grandfather's family were Italian emigrants from Telese Terme, Campania; the family surname was originally spelled "Giammattei" (Italian pronunciation: [dʒammatˈtɛi]) before immigrating to the United States. His paternal grandmother had deep roots in New England, dating back to the colonial era. Giamatti's brother, Marcus, is also an actor, and his sister, Elena, was a jewelry designer.
Giamatti attended Choate Rosemary Hall until he graduated in 1985. Giamatti then attended Yale, where he was active in the undergraduate theater scene and worked with fellow actors and Yale students Ron Livingston and Edward Norton. He graduated in 1989 with a bachelor's degree in English, and performed in numerous theatrical productions, including on Broadway and a stint from 1989 to 1992 with Seattle's Annex Theater. Giamatti also briefly worked as an animator before returning to Yale and earning a Master of Fine Arts from the Yale School of Drama in 1994, where he studied with Earle R. Gister.
He made his television debut in the ABC made for television film She'll Take Romance (1990). After minor roles in the neo-noir Past Midnight (1991) and the romantic comedy Singles (1992) he acted in Woody Allen's comedy film Mighty Aphrodite (1995) and Sydney Pollack's romantic comedy remake Sabrina (1995). That same year in March, he made his Broadway debut in Tom Stoppard's Arcadia portraying Ezra Chater. Vincent Canby describe the role as being "a helplessly funny subsidiary" one. In November he portrayed The Rev. Donald Bacon in David Hare's Racing Demon. Both of these productions took place at the Lincoln Center Theater.
In 1997, Giamatti landed his first high-profile role as Kenny "Pig Vomit" Rushton in the film adaptation of Howard Stern's Private Parts. Stern praised Giamatti's performance often on his radio program, calling for him to be nominated for the Academy Award for Best Supporting Actor. Roger Ebert of the Chicago Sun-Times described Giamatti's performance as being "well played". That same year he reunited with Woody Allen, acting in the comedy Deconstructing Harry (1997). He also took a small but memorable role as Richard the Bellman in the Julia Roberts-led romantic comedy My Best Friend's Wedding (1997). That same year he returned to Broadway, playing Andrei Prozorov in the revival of Anton Chekov's Three Sisters.
In 1998, Giamatti appeared in Season 6, Episode 15 of “Homicide: Life on the Street." He played Harry Tjarks, who raised pit bulls and was more concerned about his dogs than the fact that they had mauled his grandfather to death. He also appeared in a number of supporting roles in big-budget films including Peter Weir's drama The Truman Show, Steven Spielberg's World War II drama Saving Private Ryan, and the action thriller The Negotiator. In 1999, he played Bob Zmuda and Tony Clifton in Miloš Forman's Andy Kaufman biopic, Man on the Moon. Giamatti continued working steadily during the early 2000s by appearing in major studio releases including Duets (2000), Big Momma's House (2000), Planet of the Apes (2001) and Big Fat Liar (2002).
In 2003, Giamatti began to earn critical acclaim after his lead role in the film American Splendor. In 2004, Giamatti gained mainstream recognition and fame with the independent romantic comedy Sideways. His portrayal of a depressed writer vacationing in the Santa Barbara wine country garnered him a Golden Globe nomination and an Independent Spirit Award and he was named Best Actor in a Leading Role by several significant film critics groups (New York, Chicago, Toronto, San Francisco, Online Film Critics).
Following the commercial success of Sideways, Giamatti appeared in Cinderella Man, for which he earned an Academy Award nomination for Best Supporting Actor. He was nominated for a Golden Globe and won the Screen Actors Guild Award for Best Supporting Actor - Motion Picture. In 2006, Giamatti was the lead in M. Night Shyamalan's Lady in the Water, a supernatural thriller, followed by the animated film The Ant Bully, and Neil Burger's drama The Illusionist co-starring Edward Norton.
Giamatti had his first major role in an action movie in the 2007 film Shoot 'Em Up, while starring in The Nanny Diaries and Fred Claus. In 2008, Giamatti received an Emmy Award for Outstanding Lead Actor in a Miniseries or a Movie for his title performance in the 2008 HBO miniseries John Adams, as well as his first Golden Globe Award for Best Actor - Miniseries or Television Film, and also earned a Screen Actors Guild award. Barry Garron of The Hollywood Reporter praised his performance, writing "Giamatti is brilliant as Adams. He is fearless in his portrayal, confident that the character’s all-consuming sacrifices for his fledgling nation will more than compensate for his numerous character flaws". William Thomas of Empire agreed, adding "The acting, especially from Giamatti as the irascible Adams and Laura Linney as his wife Abigail, who steered him clear of vanity...has the tang of authenticity, even when burdened with great gulps of politicking". That same year, he starred in the independent film Pretty Bird, which is a fictionalized retelling about the drama behind the invention of a rocketbelt.
Giamatti received his second Golden Globe win for Best Actor in a Motion Picture - Musical or Comedy for his role in the 2010 film, Barney's Version. The Associated Press praised Giamatti, describing it as "pitch perfect", adding, "the picture undoubtedly will draw kudos in its home and native land and likely beyond, buoyed by that virtuoso Giamatti performance". Giamatti starred as the lead in the comedy-drama film Win Win, which earned positive reviews from critics. Scott Tobias of NPR wrote of his performance, "By now, the Giamatti persona has been well-defined — exasperation and despair, tempered by mordant wit—but the actor's every performance is like a snowflake, and here McCarthy provides him a role that's subtly down-to-earth". The same year he had small roles in Ironclad, The Hangover Part II and The Ides of March.