Walker was born in Binghampton, New York on November 19, 1878, attended Buffalo Central High School, and later Rochester University from which he graduated in 1897. He spent the next four years taking classes at the Art Students League in New York, studying under Frank Vincent DuMond. His brother William H. Walker, also a cartoonist, became the chief editorial cartoonist for Life at the end of the 1890s. Both brothers lived and worked in Flushing, New York. Walker died of a heart attack while shoveling snow on January 22, 1947.