Giải Oscar cho nam diễn viên chính xuất sắc nhất
Danh sách cụ thể > Thập niên 1940

| Năm | Diễn viên | Phim | Vai diễn | Chú thích |
| --- | --- | --- | --- | --- |
| 1940  (13)  | James Stewart ‡ | The Philadelphia Story | Macaulay "Mike" Connor |  |
| 1940  (13)  | Charlie Chaplin | The Great Dictator | Adenoid Hynkel/The Barber |  |
| 1940  (13)  | Henry Fonda | The Grapes of Wrath | Tom Joad |  |
| 1940  (13)  | Raymond Massey | Abe Lincoln in Illinois | Abraham Lincoln |  |
| 1940  (13)  | Laurence Olivier | Rebecca | 'Maxim' de Winter |  |
| 1941  (14)  | Gary Cooper ‡ | Sergeant York | Trung sĩ Alvin C. York |  |
| 1941  (14)  | Cary Grant | Penny Serenade | Roger Adams |  |
| 1941  (14)  | Walter Huston | The Devil and Daniel Webster | Mr. Scratch |  |
| 1941  (14)  | Robert Montgomery | Here Comes Mr. Jordan | Joe Pendleton |  |
| 1941  (14)  | Orson Welles | Công dân Kane | Charles Foster Kane |  |
| 1942  (15)  | James Cagney ‡ | Yankee Doodle Dandy | George M. Cohan |  |
| 1942  (15)  | Ronald Colman | Random Harvest | Charles Rainier |  |
| 1942  (15)  | Gary Cooper | The Pride of the Yankees | Lou Gehrig |  |
| 1942  (15)  | Walter Pidgeon | Mrs. Miniver | Clem Miniver |  |
| 1942  (15)  | Monty Woolley | The Pied Piper | Howard |  |
| 1943  (16)  | Paul Lukas ‡ | Watch on the Rhine | Kurt Muller |  |
| 1943  (16)  | Humphrey Bogart | Casablanca | Rick Blaine |  |
| 1943  (16)  | Gary Cooper | For Whom the Bell Tolls | Robert Jordan |  |
| 1943  (16)  | Walter Pidgeon | Madame Curie | Pierre Curie |  |
| 1943  (16)  | Mickey Rooney | The Human Comedy | Homer Macauley |  |
| 1944  (17)  | Bing Crosby ‡ | Going My Way | Cha xứ Chuck O'Malley |  |
| 1944  (17)  | Charles Boyer | Gaslight | Gregory Anton |  |
| 1944  (17)  | Barry Fitzgerald | Going My Way | Father Fitzgibbon |  |
| 1944  (17)  | Cary Grant | None but the Lonely Heart | Ernie Mott |  |
| 1944  (17)  | Alexander Knox | Wilson | Woodrow Wilson |  |
| 1945  (18)  | Ray Milland ‡ | The Lost Weekend | Don Birnam |  |
| 1945  (18)  | Bing Crosby | The Bells of St. Mary's | Cha Chuck O'Malley |  |
| 1945  (18)  | Gene Kelly | Anchors Aweigh | Joseph Brady |  |
| 1945  (18)  | Gregory Peck | The Keys of the Kingdom | Father Francis |  |
| 1945  (18)  | Cornel Wilde | A Song to Remember | Frédéric Chopin |  |
| 1946  (19)  | Fredric March ‡ | The Best Years of Our Lives | Al Stephenson |  |
| 1946  (19)  | Laurence Olivier | Henry V | Vua Henry V của Anh |  |
| 1946  (19)  | Larry Parks | The Jolson Story | Al Jolson |  |
| 1946  (19)  | Gregory Peck | The Yearling | Ezra "Penny" Baxter |  |
| 1946  (19)  | James Stewart | It's a Wonderful Life | George Bailey |  |
| 1947  (20)  | Ronald Colman ‡ | A Double Life | Anthony John |  |
| 1947  (20)  | John Garfield | Body and Soul | Charlie Davis |  |
| 1947  (20)  | Gregory Peck | Gentleman's Agreement | Philip Schuyler Green |  |
| 1947  (20)  | William Powell | Life with Father | Clarence Day, Sr. |  |
| 1947  (20)  | Michael Redgrave | Mourning Becomes Electra | Orin Mannon |  |
| 1948  (21)  | Laurence Olivier ‡ | Hamlet | Hoàng tử Hamlet của Đan Mạch |  |
| 1948  (21)  | Lew Ayres | Johnny Belinda | Tiến sĩ Robert Richardson |  |
| 1948  (21)  | Montgomery Clift | The Search | Ralph "Steve" Stevenson |  |
| 1948  (21)  | Dan Dailey | When My Baby Smiles at Me | "Skid" Johnson |  |
| 1948  (21)  | Clifton Webb | Sitting Pretty | Lynn Aloysius Belvedere |  |
| 1949  (22)  | Broderick Crawford ‡ | All the King's Men | Willie Stark |  |
| 1949  (22)  | Kirk Douglas | Champion | Michael "Midge" Kelly |  |
| 1949  (22)  | Gregory Peck | Twelve O'Clock High | Trưởng lữ đoàn Frank Savage |  |
| 1949  (22)  | Richard Todd | The Hasty Heart | Ha sĩ Lachlan "Lachie" MacLachlan |  |
| 1949  (22)  | John Wayne | Sands of Iwo Jima | Trung sĩ John M. Stryker |  |