He had a college scholarship to play soccer, but he decided to go to University of Oregon, where he studied Psychology.
In 1997 Efferding stopped competing in both sports in order to pursue business opportunities, but continued lifting.
At the age of 38, Efferding came back to bodybuilding and competed in the 2006 Seattle Emerald Cup, winning the Superheavyweight class weighing 235 lbs.
Efferding earned his IFBB Pro Card on July 17, 2009, winning the Superheavyweight class and overall award at the Masters Nationals Bodybuilding Championships weighing 259 lbs.
On May 15, 2011, Stan entered the 2011 SPF California State Championships and competed raw without knee wraps.