In 1943, along with Slugger, stopped a bank robbery by the Time-Keeper.
As a result of scientific alteration, his body is at the very peak of athleticism.
He and Slugger were active in the European theater of World War II.
There is conflicting information about the All-American. One report has him being killed by a sniper's bullet in the Korean War as mentioned in the 2004 Visitor's Guide, while Elliot Mills mentions that the All-American along with the Lamplighter had just retired in 1959. That suggests the possibility that someone else, possibly a grown-up Slugger, donned the costume and assumed the role of the All-American for a handful of years following Appleton's death.
It's also possible the Visitor's Guide was wrong or maybe Mills, misspoke meaning some other hero had just retired, though there hasn't been too many heroes established along the same time frame as the Lamplighter and the All-American.
There could also be a link between the All-American and Slugger somehow involved in the the Commando K Project and U.S. Government covert operations.