Making his breakthrough film role in Alexander Korda's The Private Life of Henry VIII (1933), today he is best remembered for his roles in The Count of Monte Cristo (1934), Alfred Hitchcock's The 39 Steps (1935), and Goodbye, Mr. Chips (1939), for which he won the Academy Award for Best Actor as the gentle English schoolmaster Mr. Chips.

In his book, The Age of the Dream Palace, Jeffrey Richards wrote that Donat was "British cinema's one undisputed romantic leading man in the 1930s".

[10] Donat made his first stage appearance in 1921, at the age of 16, with Henry Baynton's company at the Prince of Wales Theatre, Birmingham, playing Lucius in Julius Caesar.

[11] In 1928, he began a year at the Liverpool Playhouse, starring in plays by John Galsworthy, George Bernard Shaw and Harold Brighouse, among others.

[16] In 1931, he achieved notice as Gideon Sarn in a dramatisation of the Mary Webb novel, Precious Bane, and he played various roles at the 1931 Malvern Festival.

[18] MGM producer Irving Thalberg spotted him on the London stage in Precious Bane, and offered him a part in the 1932 film Smilin' Through, which he declined.

Donat's first great screen success came in his fourth film, playing Thomas Culpeper in The Private Life of Henry VIII (1933), also produced by Korda.

At the 1933 Malvern Festival, Donat received good reviews for his performance in A Sleeping Clergyman, which transferred to the West End.

[26] The Count of Monte Cristo was successful and Donat was offered the lead role in a number of films for Warners, including Anthony Adverse (1935) and another swashbuckler, Captain Blood (1935).

For the first time on our screen we have the British equivalent of a Clark Gable or a Ronald Colman, playing in a purely national idiom.

"[29] Hitchcock wanted Donat for the role of Edgar Brodie in Secret Agent (1936) and Detective Ted Spencer in Sabotage (1936), but this time Korda refused to release him.

Madeleine Carroll had read the James Hilton novel while shooting The 39 Steps, and had persuaded Donat that it could be a good second film for them to star in together.

Donat was caught up in the furore, and the stress was so great that he suffered a nervous collapse a few days into the shooting and had to enter a nursing home.

Dietrich, whose contract with Korda was for $450,000, threatened to leave the project if that happened, and production was halted for two months, until Donat was able to return to work.

[34] He planned to return to the U.S. in 1937 to make Clementine for Small at RKO but changed his mind, fearing legal reprisals from Warners.

[36][37] In The Citadel (1938), he played Andrew Manson, a newly qualified Scottish doctor, a role for which he received his first Best Actor Oscar nomination.

"[39] Australian film critic Brian McFarlane writes: "Class-ridden and sentimental perhaps, it remains extraordinarily touching in his Oscar-winning performance, and it ushers in the Donat of the postwar years.

"[40] His rivals for the Best Actor Oscar were Clark Gable for Gone with the Wind, Laurence Olivier for Wuthering Heights, James Stewart for Mr. Smith Goes to Washington and Mickey Rooney for Babes in Arms.

[41] MGM wanted Donat to star in a movie about Beau Brummell and a new version of Pride and Prejudice but that was delayed by the war.

[citation needed] He had the title role in the film The Young Mr. Pitt (1942) for 20th Century Fox and played Captain Shotover in a new staging of Heartbreak House at the Cambridge Theatre in London from 1942 to 1943.

In 1943, he took over the lease of the Westminster Theatre, staging a number of plays there until 1945, including An Ideal Husband (1943–44), The Glass Slipper (1944) and The Cure for Love (1945) by Walter Greenwood.

[43][44] Donat was reunited with Korda for the film Perfect Strangers (1945), known in the United States as Vacation from Marriage, with Deborah Kerr.

In early 1947, immediately following his release from MGM-British, Eagle-Lion Films planned to shoot Gerald Butler's Kiss the Blood Off My Hands with Donat in the lead and purchased the screen rights to the novel.

[51] He was cast as Thomas Becket in T. S. Eliot's Murder in the Cathedral in Robert Helpmann's production at The Old Vic theatre in 1952 but, although his return to stage was well received, his illness forced him to withdraw during the run.

His biographer Kenneth Barrow said he had "... a brain tumour the size of a duck egg and cerebral thrombosis was certified as the primary cause of death".