Shriner was born in New York City, New York, the twin brother of soap opera actor Kin Shriner and the son of Eileen “Pixie” McDermott and Herb Shriner, a Hoosier humorist who had several shows in the early days of television, including Two for the Money and The Herb Shriner Show. Wil made his first appearance on The Tonight Show Starring Johnny Carson and then went on to be a regular on the NBC morning show The David Letterman Show. For one season in the 1980s (1987–88), he hosted The Wil Shriner Show, a nationally-syndicated Group W television talk show. TV Guide described the program as "a daily variety-talk show featuring celebrity guests, segments on health and fitness, and interviews with authors and experts."