He won a scholarship to the Rose Bruford Drama College, where he received a BA in Drama in 1979. He later studied with the Greenwich Young People's Theatre and went on to appear in a number of stage plays including The Pope's Wedding, for which he received Time Out's Fringe Award for Best Newcomer of 1985 - 1986 and the British Theatre Association's Drama Magazine Award as Best Actor of 1985.

Oldman first appeared on screen in the film Remembrance in 1982, going on to win his first starring role in Sid and Nancy (1986), in which he played the rocker Sid Vicious. He has become known for playing eccentrics and for his mastery of accents. He has played a variety of famous characters including Dracula, Ludwig van Beethoven, Lee Harvey Oswald, Commissioner Gordon, Shakespeare's Rosencrantz, Sid Vicious, Albert Milo, Sirius Black, Pontius Pilate and the Devil. Other roles that would be a stretch for any other actor include the roles of a pimp, a disfigured serial killer victim, an aged Senate chairman, a futuristic villain, a few corrupt cops, a sadistic prison warden, a Russian terrorist a violent football hooligan and the villain on Lost in Space

In 1997 he directed, produced, and wrote Nil by Mouth, partially based on his life, which went on to win the Alexander Korda Award for Best British Film, a BAFTA Award, the Channel 4 Director's Award, and the Empire Award, and was declared by the British Academy of Film and Television Arts as one of the one hundred best films of all time despite containing the word "fuck" 470 times, a record that stood until the 2005 release of The Devil's Rejects.

Oldman has been married three times: to Lesley Manville (1987 - 1990), to Uma Thurman (1990 - 1992), and to Donya Fiorentino (1997 - 2001).