He was promoted to defensive coordinator and recruiting coordinator on January 11, 2019.

"Mike Horowitz has shown incredible loyalty and demonstrated the ability to make an impact coaching at both end of the field, as well as the specialty positions," said Saint Joseph's head coach Taylor Wray upon the announcement of Horowitz's promotion. "Mike has been a jack of all trades, and I think that has helped him become a very well-rounded coach. He served as the defensive coordinator with both the Israeli U-19 National Team and the Israeli Senior Men's National Team at the FIL World Championships. He has proven he is ready to handle the added responsibility of being the defensive coordinator here at SJU."

After serving as a volunteer assistant coach in 2014-15, Horowitz was promoted to assistant coach for the 2016 campaign and assisted in all facets of the program, with a specific focus on mentoring SJU's goalkeepers, face-off unit and coordinating the riding and clearing game. In his first two seasons ('15, '16), he assisted at the defensive end, scouting and organizing the scout team offense. In his third and fourth seasons (’17, ‘18) he worked at the offensive side in the opposite roles. In his fifth and sixth seasons (’19, ’20), Horowitz moved into the defensive coordinator and recruiting coordinator role.

In the six seasons Horowitz has been on Hawk Hill, Saint Joseph's produced the 2016 Northeast Conference Defensive Player of the Year in T.J. Jones and the 2019 Rookie of the Year in face-off specialist Zach Cole in addition to four All-Conference goalkeepers, four All-Conference close defensemen, four All-Conference long stick midfielders, and three All-Conference face-off specialists and saw the Hawks earn 17 NEC Defensive Player of the Week honors.

From 2017-2020, Horowitz coached 2020 Inside Lacrosse All-American Honorable Mention and Tewaaraton Award Watch List goalkeeper Mike Adler, who finished his Hawk Hill career ranked fourth in career save percentage (56.9%), fifth in goals against average (9.37), and fifth in career saves (426).

In a shortened 2020 season, Adler tied for third nationally in total saves (95) and led the NEC in both goals against average (9.42) and save percentage (59.4%), finishing the season with three NEC Defensive Player of the Week accolades.

In 2018, Adler turned in a rookie campaign for the ages.