Lavelle represented the United States at multiple youth levels before making her senior international debut in 2017. After finishing her collegiate career with the Wisconsin Badgers in 2016, Lavelle began her professional career with Boston Breakers before moving to Washington Spirit a year later. She started six games for the United States at the 2019 World Cup, scoring three goals, and was awarded the Bronze Ball. The same year, she was named the sixth best player in the world at The Best FIFA Football Awards 2019 and was named to the 2019 FIFA FIFPro World XI. In the 2020 Olympics, she scored one goal for the United States on the way to a bronze medal.