Oldman began acting on stage in 1979, and gained his first starring film role in Meantime (1983). He continued to lead a successful theatre career, during which he performed at London's Royal Court and was a member of the Royal Shakespeare Company, with credits including Cabaret (1979), The Massacre at Paris (1980), Entertaining Mr Sloane (1983), Saved (1983), The Country Wife (1987) and Hamlet (1987). Oldman's portrayals of Sid Vicious and Joe Orton, in the films Sid and Nancy(1986) and Prick Up Your Ears (1987), respectively, prompted critic Roger Ebert to describe him as "the best young British actor around". Identified with the "Brit Pack", Oldman gained further domestic recognition as a football firm leader in The Firm (1989) and the titular Rosencrantz in Rosencrantz & Guildenstern Are Dead (1990). He increasingly starred as offshore characters during the early 1990s, playing a Hell's Kitchen gangster in State of Grace (1990), Lee Harvey Oswald in JFK (1991) and Count Dracula in Bram Stoker's Dracula (1992).
Oldman went on to star as the antagonists of films such as True Romance (1993), The Fifth Element (1997), Air Force One (1997) and The Contender (2000); corrupt DEAagent Norman Stansfield, whom Oldman portrayed in Léon: The Professional (1994), has been ranked as one of cinema's greatest villains. He meanwhile gave an acclaimed reading of Ludwig van Beethoven in Immortal Beloved (1994). In the 21st century, Oldman is known for his roles as Sirius Black in the Harry Potter series, James Gordon in The Dark Knight Trilogy, Lord Shen in Kung Fu Panda 2 (2011), George Smiley in Tinker Tailor Soldier Spy (2011), a human leader in Dawn of the Planet of the Apes (2014), and Winston Churchill in Darkest Hour (2017), which earned him the Academy Award for Best Actor. Films in which he has starred have grossed over $11 billion.
Outside of acting in film, Oldman wrote and directed Nil by Mouth (1997); featured in television shows, such as Fallen Angels, Tracey Takes On... and Friends; appeared in music videos for David Bowie, Guns N' Roses and Annie Lennox; and provided the voice of Viktor Reznov in the Call of Duty video game series.