Comic artist and writer Addison Morton "Mort" Walker was born in El Dorado, Kansas on September 3, 1923. His father, Robin Adair Walker, was an architect and his mother, Carolyn Richards Walker, was a newpaper illustrator. His family relocated to Kansas City, Missouri when he was still a child, and he began illustrating for his elementary school newletter at age eleven. At age twelve he sold his first cartoon to a local publication. By the age of fourteen he was regularly contributing cartoons to Child's Life, Flying Aces, and Inside Detective magazine, and by eighteen he was chief editorial designer for Hallmark. 

From 1942-'43 he attended Kansas City Junior College and then the University of Missouri before being drafted in the U.S. Army, serving as an intelligence and investigating officer during World War II. He was posted in Italy until he was discharged in 1947. Returning to the U.S., he finished his studies at the University of Missouri in Columbia, graduating in 1948. Walker then moved to New York to pursue cartooning full time. After working for a few years as an editorial cartoonist at the Saturday Evening Post, he developed the "Beetle Baily" multi-panel cartoon and found syndication through King Features Syndicate. He would eventually have an international daily readership of around 200 million. 

Walker created and collaborated on several other strips, among them "Hi and Lois" with Dik Browne, "Sam and Silo" with Jerry Dumas, the strip "Boner's Ark" under the penname "Addison," and "Sam's Strip," "Mrs. Fitz's Flats," "Gamin and Patches," and others under his own name.

In addition to his artistic output, Walker was interested in the preservation of cartooning history after noticing, while working for King Features Syndicate in the late 1940s, that employees were using original cartoon drawings to sop up water leaks. He began collecting discarded works and in 1974, with a grant from the William Randolf Hearst Foundation, he founded the Museum of Cartoon Art, the first of its kind, in Greenwich, CT. His collection would grow to include over 200,000 pieces, among them original Mickey Mouse cartoons by Ub Iwerks and original panels from Chester Gould, Hal Foster, Bil Keane, and many internationally-renowned cartoonists. It would eventually become the International Musuem of Cartoon Art before being moved to the Billy Ireland Cartoon Library & Museum at Ohio State University, Columbus, OH. 

Walker received various awards and recognition for his work and his preservation work throughout his life. The National Cartoonists Society gave him the Reuben Award for Outstanding Cartoonist of the Year for "Beetle Bailey" in 1953, the Elzie Segar Award in 1977 and 1999, the Humor Strip Award in 1966 and 1969, and the Gold T-Square Award in 1999. In 1979 he was awarded the Comic Con International's Inkpot Award, and in 2010 he received the Sparky Award for lifetime acheivement from the Cartoon Art Museum. He was given the American Legion's Fourth Estate Award in 1978, the Decoration for Distinguished Civilian Service by the U.S. Army in 2000, and was honored in 2017 by the New York Yankees for his service in World War II.

Mort Walker died on January 27, 2018, at his home in Stamford, Connecticut.