Born and raised in Pittsburgh, Pennsylvania, Andy attended Carrika High School, where he participated in three sports - football, swimming and track - before graduating in 1957.
Andy attended Washington and Jefferson College for one year and then transferred to Lafayette College. He participated in track and swimming at Lafayette and set numerous swimming records. He graduated in 1961 with a degree in Psychology, then stayed at Lafayette as an assistant Dean of Admissions.
In 1962, Andy moved on to Bucknell University, where he also served as an assistant Dean and started his graduate studies. In 1963, he received a Masters in Psychology and, during the fall of that same year, was hired at Lake Forest College as assistant Dean of Students.
While at Lake Forest, Andy coached numerous sports, including tennis, cross country and track, but he made his biggest impression in the sport of hockey, where he has been called "the father of Lake Forest hockey". Andy was appointed the team's club coach in 1964, and was instrumental in the sport's elevation to varsity status the following season. He also oversaw the hockey team's move indoors to the Alumni Memorial Fieldhouse in 1970. Andy transformed a fledgling hockey program with a scant 6-game schedule into one of the College's most popular sports that played nearly 30 contests per season. As the team's first varsity coach, Sweet compiled an eight-year record of 90-69-1 with only one losing season, and produced multiple All-Americans. His teams did so while playing much larger schools, including many from the Big Ten. What makes Sweet's coaching accomplishments even more remarkable is the fact that he coached the team without the benefit of ever having played hockey until he came to Lake Forest. In fact, he first took the ice in a pair of sneakers. He progressed steadily until, by 1970, he was practicing with the team as a player as much as a coach.
Andy left Lake Forest in 1973 to fulfill an ambition to farm, but also found time to serve three years as the secretary/treasurer of the American Collegiate Hockey Association.