Al Capp veterans returning from the war. Capp was also involved with the Sister Kenny Foundation, which pioneered new treatments for polio in the 1940s. Serving in his capacity as honorary chairman, Capp made public appearances on its behalf for years, contributed free artwork for its annual fund-raising appeals, and entertained crippled and paraplegic children in children's hospitals with inspirational pep talks, humorous stories and sketches. In 1940, an RKO movie adaptation starred Granville Owen (later known as Jeff York) as Li'l Abner, with Buster Keaton taking the role of Lonesome Polecat, and featuring a title song with lyrics by Milton Berle.
Al Capp have stressed that the cartoonist also had a sensitive side; in 1973, when learning that the son of his political rival Ted Kennedy had had his right leg amputated, Capp wrote the boy a letter of encouragement, giving candid advice as to how to deal with the loss of a limb, which he himself had experienced as a boy. One of Capp's grandchildren recalls that at one point, tears were streaming down the cartoonist's cheeks while he was watching a documentary about the Jonestown massacre. Capp is also reported to have given money anonymously to charities and "people in need"