From 1975 to 1981, Collins coached at Southern Miss, and compiled a 48–30–2 record. In 1982 he was hired by SMU, signing a five-year deal with more than $100,000 annual salary. While at SMU, Collins compiled a 43–14–1 record. His only losing season as a coach came in 1976, when he went 3–8 at Southern MIss. From 1982 to 1984, he put together the best stretch in SMU's history, going 31–4–1.