[citation needed] In September 2020, Lee entered the qualifying round of the French Open, her first Grand Slam tournament ever played.

[4][5] Lee recorded her first WTA Tour match win at the 2021 Poland Open as a lucky loser over Cypriot qualifier Raluca Serban.

[6] In 2022, she qualified into the main draw of the Charleston Open for a second year in a row but lost to Jasmine Paolini.

[8] Having qualified for the 2023 Montevideo Open, Lee defeated wildcard entrant Lucía de Santa Ana to reach the second round,[9] where she was double baggled by second seed and eventual champion Renata Zarazúa.

[12] Later that year, Lee qualified for the 2024 Fifth Third Charleston 125 2, where wins over lucky loser Kayla Cross[13] and eighth seed Iva Jovic saw her reach the quarterfinals,[14] at which point her run was ended by wildcard entrant Lauren Davis in three sets.