Waltert has career-high WTA rankings of 107 in singles, achieved on 12 June 2023, and 180 in doubles, reached on 7 March 2022.

[citation needed] Waltert made her WTA Tour main-draw debut at the 2019 Ladies Open Lausanne, where she received a wildcard for the singles and doubles tournaments.

[3][4][5] By defeating Cristina Bucsa the second round, she went one step further to reach her first WTA Tour quarterfinal, where she was beaten by Olga Danilović.

[citation needed] Waltert made her major debut at the 2023 French Open[8] and won her first match defeating Elizabeth Mandlik,[9] before losing in the second round to Elisabetta Cocciaretto.

[citation needed] Partnering with María Lourdes Carlé, Waltert was runner-up in the doubles at the WTA 125 2024 Montreux Nestlé Open, losing to Quinn Gleason and Ingrid Martins in the final which went to a deciding champions tiebreak.