Tolkin, a rugby coach since 1986, was an English teacher at Xavier High School in New York, where he was the coach for the schools senior rugby team. He had an impressive record with the school, coaching them to three National Championships, six National Championship games, 17 National Championship Semifinals, and 20 Regional Championships.
In 2000, he served as head coach of the New York Athletic Club in the Rugby Super League from 2000-2011. In 12 years, NYAC won three national championships during Tolkin's tenure. Having led NYAC to the national championship (along with leading Xavier to a national championship and his role as defensive coach for the USA Eagles) resulted in Mike Tolkin winning the 2010 Coach of the Year award by We Are Rugby magazine and by RugbyMag.
In 2008, Tolkin joined the United States national side as defence coach, which saw him play pivotal part in their 2011 Rugby World Cup campaign. The Eagles played well defensively during the 2011 RWC, limiting Tier 1 countries Ireland and Italy to 22 and 27 points respectively, and holding Russia to only 6 points. His ability to get the best out of players, which saw him specialize in talent identification and player development serving as a talent recognition selector in 2001 for former USA Head Coach Tom Billups, saw Tolkin promoted to Head Coach in 2012, taking over from Irish man Eddie O'Sullivan.