Strongman debuted in CRASH COMICS #1 (May 1940) and ended his career in the final issue, #5 (Nov 1940). That's his claim to fame.
When it comes to golden-age heroes, there's either an abundance of info about them online, or next to nothing. Strongman falls in the latter category. And even when you find it, it's not always accurate. One profile for Strongman says he gained his powers from drinking a potion and debuted in CRASH COMICS #2.
Studying the secrets of the yogi, Percy van Norton turned himself into the perfect human. He ran around as a ne'er-do-well playboy to protect his secret life. He was basically Holyoke's take on Superman. He wore glasses in his secret identity. He had super strength, super breath, was nigh-invulnerable... His costume was even in primary colors!
Although there's no evidence to suggest it, I wonder if Strongman's short career could be attributed to DC's strong-arming of Superman clones. He appeared at the same time that DC struck down Fox's Wonder Man and Fawcett's Master Man -- and disappeared nearly as quickly. Maybe DC never had a chance to file a formal complaint. They may have simply said, "Yo. No." and Holyoke just decided not to fight it.