Richard St. John Harris (1 October 1930 – 25 October 2002) was an Academy Award-nominated and Grammy Award-winning Irish actor, singer and songwriter. He appeared on stage and in many films, and is perhaps best known for his roles as King Arthur in Camelot (1967), as Oliver Cromwell in Cromwell and for his portrayal of Albus Dumbledore in Harry Potter and the Philosopher's Stone (2001) and Harry Potter and the Chamber of Secrets (2002), his last film. He also played a British aristocrat and prisoner in A Man Called Horse (1970).

Harris was born in Limerick, Ireland, one of nine children of farmer Ivan Harris and Mildred. He was schooled by the Jesuits at Crescent College. A talented rugby player, he was on several Munster Junior and Senior Cup teams for Crescent, and played for the well-respected Garryowen club. He might have become a provincial or international-standard rugby player, but his athletic career was cut short when he contracted tuberculosis in his teens. He remained an ardent fan of Munster provincial rugby team until his death, attending many matches, and there are numerous stories of japes at rugby matches with fellow actors and rugby fans Peter O'Toole and Richard Burton.

Harris made his film debut in 1958 in the film Alive and Kicking. He had a memorable bit part in The Guns of Navarone as an Australian air force pilot who reports that blowing up the "bloody guns" of the title is impossible by air. For his role in Mutiny on the Bounty, despite being virtually unknown, he insisted on third billing, behind Trevor Howard and Marlon Brando. His first star turn was in the 1963 film This Sporting Life, as a bitter young coal miner, Frank Machin, who becomes an acclaimed rugby league footballer. For his role as Frank Machin, Harris won the 1963 award for best actor at the Cannes film festival. He also won acclaim and notice for his leading role (with Charlton Heston) in Sam Peckinpah's famous "lost masterpiece" Major Dundee (1965), as an Irish immigrant-turned-Confederate cavalryman during the American Civil War.

Later in his career, Harris appeared in two Oscar-winning films, first as gunman "English Bob" in the 1992 western, Unforgiven, as well as portraying Roman Emperor Marcus Aurelius in Ridley Scott's Gladiator (2000).