Hanna-Barbera: Tom and Jerry (1939-1957)

Friz Freleng, briefly assigned to work under Harman, had returned to Schlesinger after his MGM contract was expired in April 1939, and storyman Joseph Barbera was united with director William Hanna to co-direct cartoon shorts for Rudolf Ising's unit. The partnership between Hanna and Barbera would last for more than six decades, until Hanna's death in 2001. The duo's first short together was Puss Gets the Boot in 1940, featuring an unnamed mouse's attempts to outwit a housecat named Jasper. Though released without fanfare, the cartoon was financially and critically successful, earning an Academy Award nomination for Best Short Subject (Cartoons) of 1940. On the strength of the Oscar nomination and public demand, Hanna and Barbera were assigned to direct more cat-and-mouse shorts, soon christening the characters, Tom and Jerry. 
Puss Gets the Boot didn't win the 1940 Academy Award for Best Animated Cartoon, but another MGM short, Rudolf Ising's The Milky Way did, making MGM the first studio to wrestle the Cartoon Academy Award away from Walt Disney. 
Tom and Jerry quickly became MGM's most valuable animated property. The cartoons were successful at the theatre box office, many licensed products (comic books, toys, etc.) were released to the market. 
The series would earn twelve more Academy Award for Short Subjects (Cartoons) nominations, with seven of the Tom and Jerry shorts going on to win the Academy Award: The Yankee Doodle Mouse (1943), Mouse Trouble (1944), Quiet Please! (1945), The Cat Concerto (1946), The Little Orphan (1948), The Two Mouseketeers (1951), and Johann Mouse (1952). Tom and Jerry was eventually tied with Disney's Silly Symphonies as the most-awarded theatrical cartoon series. Originally barred by Fred Quimby from making a second cat-and-mouse short until the overwhelming success of Puss Gets the Boot demanded it, Hanna and Barbera and their team of animators, who included George Gordon, Jack Zander, Kenneth Muse, Irven Spence, Ed Barge, Ray Patterson, and Pete Burness, worked on nothing but more Tom and Jerry cartoons from 1941 until 1955.