Bethune was born to Richard and Jean Bethune, both members of the United States Air Force, and has a brother.[4][5] She started playing soccer at age three or four.[6] At age four, her family moved to England for three and a half years, where she originally played with boys because there was no girls' team.[5][7] She played club soccer for the ECNL's Concorde Fire Soccer Club in Atlanta and was named to the national Best XI in 2017 and 2018.[2] She played one season of high school soccer at Alpharetta High School.[4] She also played basketball into high school but focused on soccer after tearing her ACL while training with the national under-17 team.[5][8]
Bethune played three seasons at the University of Southern California. She missed her freshman season due to a second ACL tear.[5] On her debut for the Trojans, she recorded two assists in a 4–3 overtime win against BYU in February 2021.[5][9] She scored 16 goals in the 2021 season, the third most in a season in program history, including a nine-minute hat trick in the first round of the 2021 NCAA tournament.[4][10] In both 2021 and 2022, as captain of the Trojans, she was named first-team All-Pac-12, first-team All-American, and the Pac-12 Midfielder of the Year.[2][5] The Los Angeles Times described her playing style as "flashy", with her game including backheel passes, chip shots, and once balancing the ball on her head to keep possession.[5]
Bethune transferred to the University of Georgia for the 2023 season, reuniting with former USC coach Keidane McAlpine, though she tore her ACL for a third time while still at USC finishing her undergraduate degree.[7][11] She led Georgia to its first postseason title in program history at the 2023 SEC tournament, where she scored an equalizer against Kentucky in the quarterfinals and the last-minute game winner against Texas A&M in the semifinals, and was named the tournament's most valuable player.[7] She was named second-team All-SEC and second-team All-American.[2]
The Washington Spirit selected Bethune third overall in the 2024 NWSL Draft; the Spirit acquired the pick by trading Sam Staab to the Chicago Red Stars.[12] She signed a three-year contract with a one-year option.[13] She scored her first professional goal late in stoppage time to beat Bay FC 2–1 on March 23.[14][15] The following month, she scored in consecutive wins against the Houston Dash on April 12 and NJ/NY Gotham FC on April 20.[14] For her performance, she was named the NWSL Rookie of the Month for March/April 2024.[16] On May 2, she assisted three times in a 4–2 win over the Chicago Red Stars, becoming the youngest NWSL player to record that many assists in one match.[17] She broke the rookie-season assist record with her seventh assist on May 10 and later that month led the league in assists, with eight.[18] She became the first player to be named back-to-back Rookie of the Month after winning again for May 2024.[19] On June 15, Bethune scored in the sixth minute of second-half stoppage time to salvage a 1–1 draw with the San Diego Wave, winning NWSL Goal of the Week.[20][21]
Bethune was called into her first senior national team camp as a training player in June 2024.[28] Later that month she was named as an alternate to the national team for the 2024 Summer Olympics in France.[29]
