Witheford started his collegiate coaching career as an assistant at Union in 2013. He quickly was promoted to assistant head coach before his third season back in Schenectady in 2015 and then spent two years as the associate head coach before finally taking over the reins of the program from former mentor Paul Wehrum.

Union registered a mark of 77-39 (.664) in his seven seasons as an assistant coach and served as the team’s defensive coordinator from 2014-19. During that time Union was consistently ranked in the top 20 nationally in both scoring defense and man-down defense, while the team saw eight All-America selections on the defensive third of the field during that time.

In his final season before taking over the head coaching position, the Dutchmen posted a 14-4 record, reached the third round of the NCAA Tournament and finished the year ranked ninth in the USILA Div. III National poll. Three players earned All-America honors, including defenseman Ed Winters and goalie Jack Santilli, while the team earned IMLCA Div. III National Coaching Staff of the Year honors.

A two-time captain of the Dutchmen, Witheford played four seasons on defense at his alma mater from 2008-11. A starter in all 63 career games, he recorded 196 ground balls and caused 82 turnovers.

As a senior in 2011, Witheford earned USILA All-America honorable mention recognition (the program's first All-America defender since 1993) and appeared in the USILA North-South All-Star Game. He was also named a USILA Scholar All-American as a senior.

Witheford was a four-time All-Liberty League Team honoree in his career, including first-team honors as a senior in 2011.