Westergaard was born on 13 July 1935 in the village of Døstrup, in the Himmerland area of Jutland. He grew up in a conservative Christian family (Inner Mission) environment in Himmerland, going to Sunday school.Westergaard was introduced to Cultural Radicalism during high school in the 1950s, which he experienced as an “epiphany” and “a liberation from the religious subjugation of his childhood.” 
Westergaard is a trained schoolteacher, educated at Ranum Seminarium. After working as a teacher for some time, he later enrolled at the University of Copenhagen to study psychology. He subsequently worked as a teacher for handicapped children, and has been principal of a school in the Djursland area for the handicapped.