Tarnow, who came to Hartford from Baldwin Wallace University in Berea, Ohio, is the sixth men's lacrosse coach in the 59-year history of Trinity's varsity program. Unfortunately, last season was cancelled due to the global pandemic, but the team experienced improvement once again. During his second spring at the helm, the Bantams finished with an 8-8 record, winning four games more than the season prior and posting its best record in seven years. The Bantams continuously showed improvement on and off the field, and the season culminated in the program's first appearance in the post-season since 2012. Tarnow mentored senior captain Scott Morgan who earned United States Intercollegiate Lacrosse Association (USILA) Warrior and New Balance All-American Second Team, NEILA All-New England First Team, and New England Small College Athletic Conference (NESCAC) All-Conference First Team honors.

Trinity finished with a 4-11 overall record in 2017-18 with six games decided by two or less goals, and saw numerous impressive individual performances. Tarnow mentored senior captain Ryan Tassan who was named to the New England Intercollegiate Lacrosse Association (NEILA) East-West Senior All Star Game after the season. The Bantams also had a successful year in the classroom as eight players earned NESCAC All-Academic honors.

Tarnow was hired as the first head coach in program history for Baldwin Wallace in 2012, where he built the program into a perennial championship contender in the Ohio Athletic Conference (OAC). He led the Yellow Jackets to the OAC semifinals in four consecutive seasons from 2014 to 2017, and to a regular-season co-championship title in 2016. Under Tarnow's guidance, the Yellow Jackets boasted the top-ranked scoring defense in all of Division III lacrosse for the past three seasons, including an average of nearly 13 points per game in 2017. Tarnow, a member of the United States Intercollegiate Lacrosse Association (USILA) All-American Committee, was named the OAC Co-Coach of the Year this spring after leading Baldwin Wallace to a 12-3 overall record and 7-1 mark in conference play.

Tarnow was also the head men's lacrosse coach at The College of Wooster for nine seasons, where his teams never had a losing season and posted a 72-51 record with a .577 winning percentage.