In Captain America's origin story, a man named Steve Rogers--who is too weak and puny to fight in World War II-is injected with a Super-Soldier Serum and develops an enhanced physique, after which he becomes Captain America and does battle with the agents of Nazi Germany. This back story was rejected by Republic during the making of this serial, as it would have required costly retakes at the time. In the serial, Captain America's real name is Grant Gardner, he is the city's district attorney and his foe is the Scarab, aka Karl Maaldor, played by Lionel Atwill.
This was the last Republic serial to be based on a comic book character.
After the movie was released the boiled wool Captain America costume was sold at auction for $5,500 and purchased by Hal Smith (I), best known as town drunk Otis Campbell on "The Andy Griffith Show" (1960), who was a huge Captain America fan. He would own the costume until his death in 1994, after which his family would once again sell the costume at auction.
Dick Purcell was both an amateur boxer and Judo 4th Dan Black Belt practitioner. Both of these qualities helped him get the role.
In 1944 Dick Purcell died of heart failure, just five months after shooting was completed..