Ms. Warner joined St. Mark's in 2013 as Associate Director of Admission and Head Coach of the Varsity girls' lacrosse team. Warner served as head coach of Varsity field hockey from 2013-2016 and in that time won two ISL titles and two New England Championships (2013, 2014), including one undefeated season in 2014. Warner also led the Varsity girls' lacrosse team to four ISL titles in 2015, 2016, 2018, and 2019. She was named "Prep Girls Coach of the Year" in 2019 by the New England Lacrosse Journal after leading her team to an undefeated season.

A 2006 graduate of Middlebury College, Warner was a versatile three-sport athlete, competing in field hockey, lacrosse and squash. Warner was a three-time All-NESCAC performer for the field hockey program and was named to the NFHCA All-Region Team in her junior and senior seasons. In 2003 and 2004, Middlebury field hockey reached the NCAA Championship Game and Warner was named to the '03 All-Tournament Team. As team captain in her senior season, Warner led the NESCAC in assists.

The Middlebury lacrosse team won the NESCAC and competed in the NCAA Final Four all four seasons from 2003-2006, with Warner starting for the program for three years. Her team also went undefeated in the NESCAC all four years. In '03 and '04 Middlebury competed in the National Championship game, winning the title in 2004 with a perfect undefeated record.

Upon graduating, Warner coached field hockey at Middlebury, then assisted at Connecticut College in both field hockey and lacrosse from 2008-2011, while earning her Masters in Psychology. From 2011-2013, Warner served as the Associate Director of Athletics and head coach of field hockey and lacrosse at The William Penn Charter School in Philadelphia.

Originally from Holderness, NH, Warner is excited to be in New England coaching, working in the admission office, and overseeing a III form dormitory. Warner lives on campus with her husband, Luke, son, Mikey, daughter, Sidney, and dog, Bear.

Ms. Guyer joined St. Mark's in 2019 as Associate Director of College Counseling. Guyer previously coached field hockey and lacrosse at St. Andrew’s School in Delaware and served as head coach of the varsity lacrosse team at Abington Friends School (PA) before coming to St. Mark’s. In 2004, she helped lead the St. Andrew’s varsity lacrosse team to a state championship.

A 2003 graduate of Harvard College, Guyer was a goalkeeper for the women’s lacrosse team and still ranks among program leaders in career and single-season saves. Before college, Guyer was a four-year participant in the USA Futures field hockey program in addition to earning all-league honors in field hockey and lacrosse and All-American recognition in lacrosse.

Originally from Philadelphia, PA, Guyer is thrilled to be back in Massachusetts and at St. Mark’s. She enjoys coaching, working with V and VI Formers through the college process, and serving on the faculty duty team in an upperform girls' dormitory. Guyer lives on campus with her cat, Peanut