Prior to turning professional, Gostisbehere played three seasons at Union College from 2011-14, compiling 82 points (22-60-82), a plus-70 rating and 85 penalty minutes in 119 games. As a junior, Gostisbehere was named Most Outstanding Player at the 2014 Frozen Four after leading the Flying Dutchmen to their first NCAA championship in program history, logging three points (1-2-3) and a plus-seven rating in a 7-4 win over Minnesota in the title game. He also helped Union capture three-consecutive ECAC tournament championships and two regular-season titles. Gostisbehere attended South Kent (Conn.) Prep from 2009-11, scoring 69 points (13-56-69) in 57 games. A native of Pembroke Pines, Fla., Gostisbehere skated with Team North America at the 2016 World Cup of Hockey, recording four assists, a plus-four rating and four penalty minutes in three games. Gostisbehere won a gold medal with Team USA at the 2013 IIHF World Junior Championship, finishing with two points (1-1-2), a plus-four rating and 25 penalty minutes in six appearances.