Which American actor was starred as Frank Cannon of "Cannon" on the first "Barnaby Jones" episode?
Barnaby Jones:  William Conrad guest-starred as Frank Cannon of "Cannon" on the first "Barnaby Jones" episode, "Requiem for a Son", and the 1975 two-part crossover episodes, "The Deadly Conspiracy". William Conrad: William Conrad (September 27, 1920 – February 11, 1994) was an American actor, producer, and director whose career spanned five decades in radio, film, and television.
William Conrad