He took over the role of Sam Spade on NBC Radio in 1950. He stayed on until the show was cancelled in 1951.
Once after he completed a water scene in Rusty Saves a Life (1949) with his canine co-star, Flame, an assistant yelled "Someone get him a towel!". A moment later he realized the towel was for the pooch.
Replaced Howard Duff as the voice of the famous private eye in "The Adventures of Sam Spade," the 1946-1951 radio series.