Kenneth Callahan was born in Spokane, Washington, on October 30, 1905, the fifth of seven children of John and Martha Ann Cross Callahan. He spent his growing years in the small town of Glasgow, Montana. Encouraged by his mother, he began painting watercolors at age seven. In 1918 he moved with his family to Raymond, Washington, then two years later to Seattle, where he took art classes at Broadway High School. Both his parents died while he was still a teenager.