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 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.

Underwood was born in Tacoma, Washington, the son of Marilyn, an interior decorator, and Frank Underwood, a United States Army colonel. As a result of his father's military career, Underwood lived on bases in the United States and Germany during his childhood. Blair attended Petersburg High School in Petersburg, Virginia. He went on to attend the Carnegie Mellon School of Drama in Pittsburgh, Pennsylvania, and is an honorary member of Phi Beta Sigma Fraternity, Inc.

Underwood's 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 Set It Off, Krush Groove, Just Cause, and Deep Impact. 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 latest role is as the recurring character Alex in the HBO series In Treatment.