Name: Paul Cassidy
First Appearance: Superman (vol. 1) #2 (Fall 1939): "The Comeback of Larry Trent"
Number of Appearances: 1
Employer: Milwaukee Journal
Note: sports writer
Paul Cassidy's byline is seen as the writer of a story titled "Trent Wins Tenth Straight Victory: Score Technical Knockout in 1st", printed in the Milwaukee Journal. This newspaper story (and Cassidy's byline) is seen in panel 7 on page 13 of Superman #2 (Fall 1939). The boxer mentioned in the headline, "Larry Trent" was actually Superman in disguise, trying to win back the world championship title for the real Larry Trent, who had been cheated out of it when his crooked manager drugged him before the title fight.
Obviously this isn't a real "character" in the traditional sense, but only a name seen in an illustration of a newspaper front page. Paul Cassidy's byline here is actually novel in one way: Nearly every newspaper story shown in the Superman stories published to this point in Action Comics and the newly-launched Superman series featured Clark Kent's own name in the byline.