Robert Hardy in 2015. (Nick Ansell/AP)

Robert Hardy, a veteran British stage and screen actor who played Minister for Magic Cornelius Fudge in the “Harry Potter” movies and was the irascible veterinarian Siegfried Farnon in the long-running TV series “All Creatures Great and Small,” died Aug. 3 in London. He was 91.

His family announced the death but did not disclose the cause.

In a career spanning seven decades, Mr. Hardy thrived primarily as a character actor with patrician good looks and a booming voice. Although he appeared in several Harry Potter films in the 2000s, he was perhaps best known for “All Creatures Great and Small,” which aired on the BBC from 1978 to 1990 and was based on James Herriot’s memoir about working as a country veterinarian.

On television, he also starred in the miniseries “Winston Churchill: The Wilderness Years” (1981), set in the decade just before the British politician came to power in 1940. New York Times TV critic Walter Goodman called Mr. Hardy’s performance “a remarkable impersonation of Churchill, complete with the aggressive slouch, the slumping stride, the truculent lower lip, the use of spectacles for peering over.”

Mr. Hardy often reprised his role as the British prime minister, including for miniseries such as “The Woman He Loved” and “War and Remembrance” (both 1988) and the TV movie “Churchill: 100 Days That Saved Britain” (2015).

In addition to many theatrical roles, he starred in a 1956 television production of “David Copperfield”; portrayed the title role in a 1960 TV version of “Henry V” opposite Judi Dench as Katherine, the Princess of France; played the swaggering Earl of Leicester in “Elizabeth R” (1971), a compelling BBC drama starring Glenda Jackson; and was Prince Albert in the TV series “Edward the King” (1975).

Timothy Sydney Robert Hardy was born in Cheltenham, England, on Oct. 29, 1925. He attended the University of Oxford, where his tutors included authors C.S. Lewis and J.R.R. Tolkien. He also befriended actor Richard Burton in a college theater club.

“We initially loathed each other,” Mr. Hardy told the Daily Telegraph decades later. “He thought I was upper class and spoilt and all that. And I thought he was presumptuous and tiresome.” They gradually bonded over a mutual worship of Shakespeare and their ability to quote verbatim large swaths of his plays.

After brief wartime training as an RAF pilot, he began his career in Shakespearean roles onstage in Stratford-upon-Avon and apprenticed under the tutelage of actor Godfrey Tearle.

Mr. Hardy played supporting roles in films such as “Torpedo Run” (1958), “The Spy Who Came in from the Cold” (1965), “10 Rillington Place” (1971), “The Shooting Party” (1985) and “Sense and Sensibility” (1995).

In his spare time, Mr. Hardy became a leading authority on the use of the longbow in medieval warfare. According to his family, he was also part of the team that raised the Tudor warship Mary Rose, which sank off England’s south coast in 1545.

His marriages to Elizabeth Fox and Sally Cooper, daughter of actress Gladys Cooper, ended in divorce. Survivors include a son from his first marriage and two daughters from his second.