Yeah, he played Friday for 31 years (1949-70). Most TV shows in the 50s were radio show spin-offs. Dragnet was no exception.
Although some spin-offs used a different cast to that of the radio shows*, there were some that used most, if not all, of the radio cast. Our Miss Brooks used almost every member of the radio cast with the exception of Jeff Chandler (he was replaced by Robert Rockwell on TV).
Other radio spin-offs include Adventures of Superman, The Adventures of Ozzie and Harriet, The Lone Ranger, Meet Corliss Archer, etc.
*A lot of radio actors didn't look like the characters they played, hence why they were replaced on TV. This is the reason why William Conrad was replaced in the Gunsmoke TV show (Conrad had played Matt Dillon on the Gunsmoke radio show).
You should check this to learn more about old time radio people:
http://www.behindthevoiceactors.com/...ad.php?t=15355