[1] While attending Brighton High School,[2] Milliman began playing lacrosse in order to stay in shape for football season.
[11] During the offseason, he chose to serve as a volunteer head coach for Team Russia at the 2014 World Lacrosse Championship after being recruited by Eugene Arkhipov.
[12] Milliman was made Richard M. Moran Head Coach of Men's Lacrosse in 2018[13] and in his first season, the team qualified for the NCAA quarterfinals for the first time in two years.
[4] The following year, he was named an assistant coach for Team USA at the 2019 World Indoor Lacrosse Championship[14] where he helped them to their fifth straight bronze medal.
[15] During the COVID-19 pandemic, Milliman was named the 23rd head coach in Johns Hopkins Blue Jays men's lacrosse history.