John Michael Leyden was born in 1908 in Grangemouth, Scotland and moved to South Africa in 1926 where he attended Natal School of Art in Durban. His first cartoon appeared in the sports pages of the Natal Advertiser in 1927. Five years of freelancing for many different South African newspapers followed his debut, after which he returned to Britain for four years, where he drew cars and motorcycles for Technical Press publications. Upon returning to South Africa, he was appointed staff cartoonist for the , and he moved to The Natal Daily News when the Tribune folded in 1939. He remained at The Daily News until retiring from full-time staff at the age of seventy three, though he continued to draw cartoons for that paper until his death. During his career, he probably published more than 20,000 cartoons for which he received the distinguished service award from the Durban Jaycees in 1984.
Leyden remains one of the most recognized South African cartoonists, with international exhibitions in Wales, Belgium, Italy, Yugoslavia, and Canada, in addition to his many exhibits around South Africa. His favorite subject to draw was the arts, particularly theatre caricatures, which he would compose during performances, doing rough sketches in the dark. In 1986, the Natal Performing Arts Council staged an exhibition of 150 of his theatre cartoons, and the University of Natal named a gallery after him when he donated many of his arts cartoons, caricatures, and originals to them. Those depicting the University and Durban Theatre Workshop productions were exhibited during the opening of the Leyden Gallery in 1981.
In addition to his arts cartooning, Leyden was famous for his character Wilbur, who wore a mustache, smoked a pipe, and represented the man on the street. Wilbur was a sports enthusiast and became so popular with readers that he sparked controversy when one reader criticized his "boring old pipe." This led to Leyden drawing a forty part series of Wilbur smoking forty different pipes, a series that is now housed in the Dunhill pipe museum in London.
- Articles about a posthumous exhibition of Jock Leyden’s work at Grangemouth High School in Scotland were published in two Scottish newspapers, Herald Scotland and The Falkirk Wheel.
- Profile of Jock Leyden via South African History Online
- All the best: Durban. Durban: Natal Daily News, 1940.
- There’s a thing!: In Aid of Prisoners of War Fund. Durban: Singleton and Williams, 1944.
- The Laugh Round Up. Durban: Natal Daily News, 1945.
- The Leyden Cartoon Book. Vol. 1-5. Cape Town: Purnell, 1963-1967.
- 100 Not Out: A Daily News Centenary Book. Durban: Daily News, 1978.
- Encore: NAPAC Theatre Cartoons. Durban: Natal Performing Arts Council, 1986.