Career
Born in Platteville, Wisconsin, Roseleip was a veteran of World World War II and the Korean War. Roseleip was a businessman. He served in the Wisconsin State Senate from 1963 to 1975.
He is perhaps best known for his failed defense of a Wisconsin law prohibiting the sale of margarine.
He was challenged to a blind taste test between butter and margarine, and he chose margarine as the better of the two. After his death, his family revealed that for years they had been serving him margarine (purchased in Iowa) instead of butter, because margarine was believed to be healthier than butter.