Callaghan played collegiate soccer at Ursinus College, making 250 career saves, fourth in school history at the end of his final season.
Following Curtin's eventual hiring by the Philadelphia Union as a member of the club's academy staff, Callaghan came on board in 2012 while continuing to serve at Villanova.
Callaghan remained with the Union through 2018, before joining the U.S. men's national team as an assistant coach and strategy analyst under Gregg Berhalter in January 2019.
The United States won 3–0 and Callaghan became the first U.S. coach to win on their debut against Mexico since David Gould in 1934 FIFA World Cup qualification.
[12] United States Raised in Ventnor City, New Jersey, Callaghan played prep soccer at Holy Spirit High School.