Always wearing his trademark gambler's visor and sunglasses, Joe Blackjack is shown playing cards against Lucy and Rerun van Pelt on several occasions. While Lucy and Rerun express awe and fear towards Joe Blackjack, his thoughts reveal cluelessness on his part.
An earlier variation on this character, Blackjack Snoopy, The World Famous Riverboat Gambler, first appeared in the strip from May 30, 1979. In his first appearance, he wears a top hat and has two mustaches. In the strip from the following day, as he sits at a blackjack table, he is wearing a gambler's visor and sunglasses and has only one mustache.