Longo began his coaching career at
Parsippany Hills High School in New Jersey, taking over a team that accumulated a .217 winning percentage over the previous 33 years. At the time of his departure, Longo left as the winningest coach in school history while leading them to their first appearance in the New Jersey state playoffs and an undefeated championship season. He accepted an assistant coaching position at
William Paterson as the assistant head coach and offensive coordinator in 2000. He left in 2002 to be the associate head coach and offensive coordinator at
La Salle and was named the head coach of the team in 2004. As head coach of La Salle, he compiled a 7–14 record over two years before leaving to accept the offensive coordinator position at
Minnesota–Duluth. He joined the coaching staff at
Southern Illinois in 2008 as the offensive coordinator. Longo joined the coaching staff at
Youngstown State in 2010 as the wide receivers coach and recruiting coordinator. Longo joined the coaching staff at
Slippery Rock in 2011 as the wide receivers coach, where his wife Tanya worked as the head coach of the university's women's basketball team. He was promoted to offensive coordinator in 2012, and the team underwent a dramatic change in offense averaging 54.5 points a game.
Sam Houston State Longo was added to the coaching staff at
Sam Houston State in 2014. In his final year at Sam Houston State, Longo's offense was one of the most prolific offenses in FCS, averaging 547 yards a game as the Bearkats went on to a 12–1 record.
Ole Miss On December 15, 2016, it was reported that Longo was hired to be the new offensive coordinator and quarterbacks coach at the
University of Mississippi. Despite averaging over 500 yards of offense per game, his offense was criticized for its inability to score in the
red zone and in clutch moments.
North Carolina Longo was named the offensive coordinator at
North Carolina in 2019. In his first three seasons as Tar Heel OC, Longo guided quarterback
Sam Howell to multiple school records, and his offense produced multiple 1,000 yard receivers and rushers.
Wisconsin On December 7, 2022, it was reported that Longo would be joining
Luke Fickell's staff at Wisconsin as the offensive coordinator and QBs coach. Longo was fired on November 17, 2024, after the Badgers started the 2024 season 5–5 (3–4 Big Ten).
Sam Houston State Longo was named head coach at
Sam Houston State in December 2024. ==Coaching philosophy==