Stephen Loomis started playing water polo when he was 13 years old in Lafayette, California. He attended Campolindo High School and grew from scoring one goal on junior varsity his freshman year to become the leading scorer, co-captain and MVP of the varsity team his senior year. He went on to attend Pepperdine University where he was a three year starter and leading scorer and All-American his senior year.
After graduating college in 2013, Stephen played with the New York Athletic Club, and professionally in Spain and Italy for five years. In 2013-14 he played for Yoin Tenerife Echeyde in the Spanish Primera Division, and led the league in assists and was top 5 in goals scored with 62. He then moved on to Rari Nantes Bogliasco in Italy where the team finished 5th overall in the league after beating Ligurian rival RN Savona in the first round of the playoffs. After 2015 Stephen signed with Albaro-Nervi water polo club in the A2 Italian league and led the league in goals scored with 58. Next he went to Rari Nantes Sori and helped the team win a decisive playout to stay in A2, with a hat trick in the final game. He finished his career in Lavagna in A2, while living in the beautiful city of Camogli.
Stephen has been coaching club water polo since 2013 coaching at CC United and Stars and Stripes Bruin water polo club. At the high school level Stephen assisted at Campolindo, and De La Salle High School, before becoming head coach of De La Salle in 2018. In 2018 Stephen also took the role of developmental coordinator for CC United. He planned a travel trip to Italy for the club in 2019, and a travel trip to Malta that same year for the De La Salle team. Stephen married his wife Giulia Sgargetta in 2018, after having met in 2016 while he was playing in Liguria, Italy.