Here some of my favourite character roles. I decided to mention just one film per actor, but honestly, most of these actors have played more than one great role, so this was just the pick of the day. Still, the Henry Fonda role is surely a top 3 one, and the Anthony Quinn role would be in my top 5 as well. The three Japanese guys I mention are sublime actors, who made many films I would recommend to anyone (especially the ones in the 1950s and 1960s, directed by Akira Kurosawa and Masaki Kobayashi).
Juror #8 by Henry Fonda in
12 Angry Men (1957)
Col. Andrea Stavros by Anthony Quinn in
The Guns of Navarone (1961)
Kôichi Nishi by Toshirô Mifune in
The Bad Sleep Well (1963)
Kambei Shimada by Takashi Shimura in
Seven Samurai (1954)
Kaji by Tatsya Nakadai in
The Human Condition (trilogy) (1959, 1959, 1961)
Lt. Commander Phillip Queeg by Humphrey Bogart in
The Caine Mutiny (1954)
Terry and Ruth Collins by Olivia de Havilland in
The Dark Mirror (1946)
A family ancestor in a portrait, Young Ascoyne D'Ascoyne (son of Lord Ascoyne D'Ascoyne), Young Henry D'Ascoyne (photographer), Reverend Lord Henry D'Ascoyne, Lady Agatha D'Ascoyne, Admiral Lord Horatio D'Ascoyne, General Lord Rufus D'Ascoyne, Ethelred D'Ascoyne and 8th Duke of Chalfont Lord Ascoyne D'Ascoyne (Banker, 9th Duke of Chalfont)
by Alec Guinness in
Kind Hearts and Coronets (1949)
Dr. Henryk Savaard by Boris Karloff in
The Man They Could Not Hang (1939)
Roger Thornhill by Cary Grant in
North by Northwest (1959)
Richard Dadier by Glenn Ford in
Blackboard Jungle (1955)
Atticus Finch by Gregory Peck in
To Kill a Mockingbird (1962)
Dr. Luther Brooks by Sidney Poitiers in
No Way Out (1950)
John J. Macreedy by Spencer Tracy in
Bad Day at Black Rock (1955)
Jefferson Smith by James Stewart in
Mr. Smith Goes to Washington (1939)
Mr. Slade, the lodger by Laird Cregar in
The Lodger (1944)
Sherlock Holmes by Basil Rathbone in
The Scarlet Claw (1944)
Victor Grandison by Claude Rains in
The Unsuspected (1947)
Otto Becker / Baron Hugo Von Detner by Conrad Veidt in
Nazi Agent (1942)
Alicia Huberman by Ingrid Bergman in
Notorious (1946)
Eric Gorman by Lionel Atwill in
Murders in the Zoo (1932)
Louise Howell by Joan Crawford in
Possessed (1947)
Col. Dax by Kirk Douglas in
Paths of Glory (1957)
Ben Stride by Randolph Scott in
Seven Men from Now (1956)
Gustave 'Gu' Minda by Lino Ventura in
Le deuxième souffle (1966)
Marshal Will Kane by Gary Cooper in
High Noon (1952)
Professor Richard Wanley by Edward G. Robinson in
The Woman in the Window (1944)
Sefton by William Holden in
Stalag 17 (1953)