Cal State Bakersfield Roadrunners After graduating, Phillips moved to
CSU Bakersfield in 2009 to study for an
M.A. in curriculum and instruction. She served as assistant coach to Nicole Van Dyke, the head coach when Phillips was recruited by CSU Stanislaus, for the
Cal State Bakersfield Roadrunners for two seasons. She also coached youth teams at Bakersfield Gunners and Turlock Tornados, and served as assistant coach at
Hilmar High School. Ahead of the 2013 season, Phillips took over as head coach when Van Dyke stepped down to take an assistant role at
Stanford. Aged 23, Phillips was the youngest head coach in Division I.
San Francisco Dons and Penn Quakers Having moved to the
San Francisco Bay Area to coach multiple youth clubs, Phillips was appointed as an assistant coach to
Jim Millinder at the
University of San Francisco in January 2015. In April 2015, Phillips once again reunited with Nicole Van Dyke, joining as her assistant coach at the
University of Pennsylvania. She spent six seasons with the
Penn Quakers, helping coach the team to an
Ivy League title in 2018.
London City Lionesses In May 2020, Phillips joined
London City Lionesses of the English second division
Championship as assistant coach to new manager Lisa Fallon. In October 2020, Fallon stepped down from the role after a winless start to the season. Phillips assumed the head coach position on an interim basis, winning her first game in charge 2–1 against
London Bees before being permanently appointed to the position the following week. She guided the team to a 6th-place finish in her debut season and finished in second-place in the
2021–22 FA Women's Championship behind
Liverpool. Despite sitting at the top of the table midway through the
2022–23 Women's Championship, Phillips resigned as London City Lionesses head coach in January 2023 in order to return to the United States and take an assistant coaching role under
Freya Coombe at
Angel City FC of the
National Women's Soccer League (NWSL).
Brighton & Hove Albion In April 2023, Phillips stood down from her role at
Angel City FC in order to return to England to join
Brighton & Hove Albion, becoming the team's third permanent head coach of the season. She signed a two-and-a-half-year contract until June 2025. The team sat bottom of the
Women's Super League at the time of her appointment. Her first game in charge was a 3–2
FA Cup semi-final defeat to
Manchester United. Four days later, the team beat
Everton 3–2 in the WSL to rise to 10th place. Phillips took seven points from the final eight WSL games of the season and retained their WSL status by finishing five points clear of relegation. On February 1, 2024, Phillips was sacked by Brighton with the team in 10th.
Arsenal Following her departure from managing Brighton, in 2024 Phillips was hired as Head of Analysis of Women's Super League side
Arsenal, with then-head coach
Jonas Eidevall saying of her "I think she combines the coaching background with an analytical background. She has some really strong points in her leadership and how she can lead a department.” She was part of the coaching staff as the club won the
2024–25 UEFA Women's Champions League. ==Coaching statistics==