Mewis joined West Ham United on Friday 22 December 2023.

Born in Weymouth, Massachusetts, Mewis began her career at a young age and quickly gained recognition for her talent. The midfielder played college soccer at Boston College, where she became one of the top players in the National Collegiate Athletic Association (NCAA).

In 2013, Mewis was drafted as the third overall pick by FC Kansas City in the National Women's Soccer League (NWSL) inaugural college draft. She played for FC Kansas City from 2013 to 2014, before joining Boston Breakers in 2015, where she would make 20 appearances, scoring six times. 

She would then experience her first taste of European football, spending a brief stint with FC Bayern Munich in Germany, before returning to Boston for the 2016 season. 2017 saw her play for three different sides, firstly with Washington Spirit, before being traded to Chicago Red Stars, and then ending the campaign with Houston Dash. 

In 2018, Mewis suffered an serious knee injury, but returned the following year to help Dash to victory in the 2020 NWSL Challenge Cup. 

After spending another season in Houston, Mewis was traded to Gotham in December 2021. Last season, she played 23 matches in the regular season and the challenge cup, where she helped the New Jersey based outfit to the NWSL Championship after victory in the play-offs. 

On the international stage, Mewis has helped her country to success in the CONCACAF Women’s Championship, as well as three SheBelieves Cup titles between 2021 and 2023. Most recently, Mewis scored from the penalty spot at the 2023 Women’s World Cup in a round of 16 defeat to Sweden.