Born in 1921 in Quincy, Illinois, Hagerbaumer grew up during the Great Depression and began duck hunting, trapping, and fishing at the age of eight in order to help support his family.

After serving in the Marines in World War II, he returned home and began working as a taxidermist in a decoy factory. He then attended San Diego State College majoring in art but never graduated. Hagerbaumer worked as preparator in the Nevada State Museum and then became a staff artist at the Santa Barbara Museum in 1957. He painted at night and sold his work at shows each weekend. It was at this point that he switched from oils to watercolor because he needed a medium that would dry faster. Soon, he realized that he coul...