Arthur played the baritone ukulele on his TV show in the 50's.
The hour-long series aired on CBS Television from January 1949 to June 1957
(as The Arthur Godfrey Show after September 1956),
then again as a half-hour show from September 1958 to April 1959.
For the old movie fans...
He played his baritone in the movie
The Glass Bottom Boat with Doris Day