O'Brien returns to Amherst after spending the previous 15 years as the head coach of women's lacrosse at Washington & Lee University, where she compiled a 221-60 (.786 win percentage) mark and was named conference coach of the year nine times. She guided the Generals to a 19-3 mark in 2022, a conference championship and a spot in the NCAA Div. III Tournament quarterfinals.

"I am excited to welcome Brooke back to Amherst," Faulstick said. "She's had amazing success at Washington & Lee and I know she'll continue to build upon the proud Amherst women's lacrosse tradition she was a part of as a student. As a faculty member at Washington & Lee she fully understands the commitment to academic excellence, and I am thrilled she brings that experience with her as well."

A native of Longmeadow, Mass., and an alumnus of the Loomis Chaffee School in Windsor, Conn., O'Brien graduated Magna Cum Laude from Amherst in 2003 with a bachelor of arts in psychology and law, jurisprudence and social thought. She earned a total of 12 letters as a member of the women's lacrosse, women's soccer and women's basketball teams and served as a captain for all three sports.

In lacrosse, she was a two-time First Team All-America selection and two-time Kelly Award winner as the Division III National Goaltender of the Year. She was named the Intercollegiate Women's Lacrosse Coaches Association (IWLCA) Division III Scholar-Athlete of the Year and was selected the Division III Women's Lacrosse Tournament's Most Outstanding Player in leading the then Lord Jeffs to the 2003 National Championship.

"I am honored and humbled to be named the next Head Coach of Women's Lacrosse at Amherst College," O'Brien said. "I want to thank Don Faulstick and the search committee for this tremendous opportunity. This is truly a dream come true – a chance to come home to the Pioneer Valley and to rejoin the talented, dynamic, and diverse Amherst community that means so much to me."

O'Brien succeeds Mammoth legend Christine Paradis, who retired as head coach at the end of the 2022 season after 28 years and 27 seasons. She finished with a career coaching record of 321-123 (.707), Her 321 wins are the 10th most by any women's lacrosse coach across all divisions of the NCAA and the 4th highest total at the Div. III level.