Like Michael Steadman, the product of a divorce, Olin made his Off-Broadway stage debut in 1978 in "Taxi Tales" and played Stanley Kowalski in "A Streetcar Named Desire" (1982), the year after making his film debut in "Ghost Story" (1981), playing John Houseman as a young man. He made his TV debut playing a cadet judging the future status of "Women at West Point" (CBS, 1979), and, in 1983, was a ballplayer in the short-lived Steven Bochco NBC series "Bay City Blues". "Hill Street Blues" and "Falcon Crest" followed before "thirtysomething" made Olin a TV star. He played Liz Taylor's agent in "There Must Be a Pony" (ABC, 1986) and starred in the miniseries "I'll Take Manhattan" (CBS, 1987). Olin also played Charles Stuart in "Good Night, Sweet Wife: A Murder in Boston" (CBS, 1990), based on the true story of the Boston man who killed his wife and blamed an African American. Olin had his first big screen lead as one of the buddies returning for a wedding in the ensemble reunion movie "Queen's Logic" (1991).
Olin began directing with a 1989 episode of "thirtysomething" and went on to handle six additional assignments. He subsequently branched out into TV-movies, directing "The Broken Cord" (ABC, 1992), about a brain-damaged Lakota Indian adoptee and the first TV-movie produced by the Fox network: "Doing Time on Maple Drive" (1992), about a dysfunctional family, which also offered Jim Carrey his first dramatic role. In 1995, Olin directed Don Johnson in HBO's "In Pursuit of Honor", which chronicled several army officers during World War I who defied orders to slaughter healthy horses. Olin made his feature film directorial debut with "White Fang 2: The Myth of the White Wolf" (1994). He returned to series TV as a police detective in the short-lived, but highly acclaimed CBS drama series "EZ Streets" (1996-97) and again in the short-lived medical drama "L.A. Doctors" (CBS, 1998-99).
Olin is married to actress Patricia Wettig, who also starred on "thirtysomething" (though not as Olin's character's spouse). The duo has worked together in the TV-movies "Cop Killer" (ABC, 1988) and "Nothing But the Truth" (CBS, 1995). Olin was also one of the executive producers of "Kansas", a 1995 ABC TV-movie starring Wettig.