Unlike some actors who would rather stick to the film genre they master at, Dermot Mulroney has taken an eclectic career path which contains diverse characters he brilliantly portrayed, certainly making him an exceptional thespian of his generation. An American of predominantly Irish descent, Dermot grew up in Alexandria, Virginia along with his four siblings from the day he was born on October 31, 1963. Already developed a fondness for acting at such a young age, he afterwards joined children's community theater which was later followed by a stage performance in "Are Teachers Human" when he was still a student of George Washington Junior High. Right after his graduation from T.C. Williams High School in 1981, he headed for Chicago, Illinois to enroll in Northwestern University where he later obtained a BFA degree by 1985.

Putting full concentration to pursue an acting career, he quickly encountered his screen debut through a CBS TV movie, "Sin of Innocence," which was aired in 1986. After playing a troubled teenager in two other TV productions of "The Drug Knot" (1986) and "Daddy" (1987), he successfully landed a major part in "Young Guns" (1988) which was also starred by the brat-pack group of Emilio Estevez, Charlie Sheen, and Kiefer Sutherland. This western flick surprisingly became a box-office hit with domestic income of more than 45 million U.S. dollar, thus automatically propelled him to earn more notice from the public plus opened his way to find better opportunity in Hollywood film industry.

Carefully selected the offers that addressed to him, Dermot wisely chose to explore various film genre rather than aimed for commercial success as seen in his 1989 projects which included a touching drama of "Unconquered", a dramatic comedy flick "Staying Together", and the adventurous "Survival Quest." It was in this latter movie that this attractive actor met and then gave his heart to actress Catherine Keener whom he finally married in 1990, the year his next film, "Longtime Companion," saw its theatrical release. From this point, he managed to maintain his career steadily with playing different characters, like a leader of a ragtag group in "Where the Day Takes You" (1992), a clueless boyfriend in "Point of No Return" (1993), and a cop tracking vicious serial killer in "Copycat" (1995). Also taking part as Winona Ryder's beau in "How to Make an American Quilt" (1995), he satisfyingly scored a Best Kiss nomination together with the actress at the 1996 MTV Movie Awards.

Dermot's career received a great boost by 1997 when he enacted a prospective bridegroom caught between Julia Roberts and Cameron Diaz in "My Best Friend's Wedding" as it scored over 299 million U.S. dollar worldwide. Focused his attention on big screen production, he then teamed up with Patricia Arquette and Don Johnson to film "Goodbye Lover" (1998) before taking his time to celebrate the birth of his first son, Clyde Mulroney, in 1999. He started the 21st century with an appearance alongside veteran actor Paul Newman also Linda Fiorentino in "Where the Money Is" (2000), followed by "Trixie" (2000) in which Nick Nolte also took part, and "The Safety of Objects" (2001) opposite Glenn Close.

Much to Dermot's delight, his next role as Randall Hertzel in Alexander Payne's gritty drama comedy, "About Schmidt" (2002), was hugely praised by critics, bringing his status grew several notches higher. After a venture into thriller genre through David Gordon Green's "Undertow" (2004), he returned to romantic comedy with "The Wedding Date" and "Must Love Dogs" which both came up in 2005. Joining the fantastic ensemble cast consisted of Sarah Jessica Parker, Luke Wilson, Diane Keaton, Rachel McAdams, also Claire Danes in "The Family Stone" (2005), he had been billed to star in "Griffin and Phoenix" (2006), a poignantly funny love story about two people who face a seemingly impassable hindrance in their life.

On June 8, 2007 Dermot filed for divorce from Catherine, his wife of over than 16 years, following their split in May 2005. Citing irreconcilable differences as the reason for the divorce, he's seeking joint legal and physical custody of their son, Clyde Keener Mulroney, while asking for property rights to be determined by the courts.