Born in 1917 in Pocahontas, Iowa to Clair and Josephine (née Wolfe) Goodyear, Mullen attended Sacred Heart High School, moving to Des Moines after graduation.
She married Oscar Eugene "Gene" Mullen (June 27, 1916 - July 1986) in 1941 and lived on a family farm near La Porte City, Iowa, supplementing her income with jobs at J. C. Penney and Santa Claus Industries.