Jay Kennedy joined King Features Syndicate in 1988 as deputy comics editor and became comics editor one year later. He was named editor in chief in 1997.

From 1983 to 1988, Kennedy served as cartoon editor of Esquire magazine, also owned by Hearst Corporation. At the same time, he  served as a humor book agent as well as a cartoon consultant and editor for  magazines and publishers, including People and Whittle Communications. In  addition, he was guest editor in 1985 for the "European Humor" issue released by the National Lampoon.

Kennedy wrote articles about the history of  cartooning, and profiled cartoonists and contemporary comics for magazines including New Age Journal, Heavy Metal, New York, The IGA Journal, and Escape, an English bi-monthly. He was also the author of "The Underground Comix Guide" (1982).

Kennedy's interest in comics was worldwide and lifelong.
Before graduating with a sociology degree from  the University of Wisconsin at Madison, Kennedy studied sculpting and conceptual art at The School of Visual Arts in New York City.

Kennedy once  explained that he chose a life in cartooning because "in the fine arts, artists generally comment on the world only obliquely; and sadly, only those people who have the leisure to study art history can fully appreciate their comments. By contrast, cartoons are an art form accessible to all people. They can simply laugh at the jokes or look beyond them to see the artist's view of the world. Cartoons are multi-leveled art accessible to everyone at whatever level they choose to enjoy."

In keeping with that philosophy, Kennedy made  a bequest of his vast personal collection of underground comics to The Ohio State University Cartoon Research Library, the preeminent library of comics and cartoon art in the country.