Messner's parents divorced when he was young, and he was raised by his mother and stepfather, Del Pretty, who ran a piano store in Livonia, Michigan. Messner referred to his biological father as the "fun" dad and Pretty as the "disciplinarian." In a 1988 interview with Mitch Albom, Messner referred to Pretty as "the most important person in my life. He's the reason I do what I do, and try as hard as I try." He later noted that Pretty "raised me, fed me, spanked me, hugged me, took me to school, wrote me poems, came to all my football games and made me feel like the most important person in the world. Pretty was diagnosed with lymph node cancer in 1980 and eventually died from the disease in December 1989 when Messner was a rookie with the Los Angeles Rams.