Artist C.C.Beck based the original Captain Marvel character design on Fred MacMurray, who was, at the time, the #1 male box-office star.
Dwayne "The Rock" Johnson was originally considering taking the role of Captain Marvel. However, he was approached by comic books fans who explained the villain, Black Adam, to him in an attempt to persuade him to take that role instead. The combination of the fans' request and the fact that the character seemed more interesting prompted Johnson to take that role instead.