Aidan Quinn was born in Rockford to devoutly Catholic, but rather itinerant parents, who raised him in Belfast, Dublin, Offaly, and other places on the island of Ireland. His father was a professor in literature and his mother a homemaker; he has an older brother, Declan Quinn, who is a noted cinematographer. Aidan Quinn got his start in the Chicago theatre at age 19. His first significant film role was in Reckless (1984), followed by a breakthrough role in Desperately Seeking Susan as the character "Dez" (the love interest of the character played by Rosanna Arquette). Quinn next starred in the controversial TV movie An Early Frost, about a young lawyer dying of AIDS (it was broadcast on NBC on November 11, 1985) and co-starred such luminaries as Gena Rowlands, Ben Gazzara and the late but not forgotten Sylvia Sidney.

Quinn lost a major role when Paramount Pictures dropped the controversial Martin Scorsese movie The Last Temptation of Christ. When Universal Pictures picked up the film, the role went to Willem Dafoe.

Since then, Quinn's roles have been mainly supporting roles in major studio films and leading roles in independent films, including appearances in The Handmaid's Tale (1990), Benny & Joon (1993), Michael Collins (1996), Practical Magic (1998) and Song For a Raggy Boy (2003). Quinn is married to the actress Elizabeth Bracco, sister of actress Lorraine Bracco.

Quinn was nominated in 1986 for an Emmy Award for lead actor in a miniseries or special for his performance in An Early Frost, but he lost to Dustin Hoffman, who won the award for his performance in Death of a Salesman. Quinn later recalled in an interview that he felt relief when he lost, because he had stage fright that night and thought there would be many more nominations in his future, an assumption that did not prove accurate.

In 2006, Quinn starred in the short lived drama The Book of Daniel which ran for 3 weeks on NBC (before being cancelled).