In 2012, Taylor Townsend made her stamp on junior tennis, becoming the first American to win the ITF Junior World Championship since 1982. She finished that year by winning both the singles and doubles juniors' titles at the Australian Open—the first American to do so since Lindsay Davenport in 1992—and three of the four junior Grand Slam doubles titles. She ended the year ranked No. 1 overall in the girls’ rankings.  

However, that epic season was not devoid of significant struggles. Townsend was infamously asked not to compete in the US Open that season due to concerns about her weight and physical fitness from the USTA. She was denied a wildcard for the US Open main draw despite earning the position the year before and being the top-ranked junior girl in the world. Her coaches declined to pay her travel expenses to attend the Open to compete, even in her guaranteed position in the juniors draw, and refused to finance any tournament appearances until she slimmed down. She refused to be kept from competition, paid her own way, and competed based on her automatic junior bid. In Taylor's own words, “I was fat, and I was black, so they took away my dream. Or at least they tried.” She made the quarterfinals in singles and won the doubles with her partner, Gabrielle Andrews. Following the controversy, Townsend parted ways with her USTA coaches and began to train under the tutelage of former world No. 4, Olympian, and 1990 Wimbledon finalist, Zina Garrison.  

At the end of that season, she officially began her professional career. In her WTA tour debut, she defeated Lucie Hradecká for her first WTA Tour-level match win. Her career-high singles rank to date occurred in August of 2024 when she reached No. 46.

In 2021, she found herself at the center of public discussion regarding her body once again, this time on her own terms. Following the birth of her son, Adyn, in March 2021, she has been extremely open and vulnerable regarding her relationship with her body and returning to training. In a fitting finale to her comeback season, Townsend was nominated to her second career Billie Jean King Cup Team, just seven months after returning to the professional circuit and seven years after she debuted for the team at 18 years old.  

After returning to professional tennis, Townsend has been quite successful on the doubles and mixed doubles fronts. She reached a then career-high ranking of world No. 5 in doubles in June of 2023 after reaching the women's doubles finals of the US Open in 2022 and the Roland-Garros women's doubles final in 2023. At the US Open in 2023, Townsend reached the mixed doubles semifinal alongside compatriot Ben Shelton. Continuing to find her stride in doubles in 2024, Taylor Townsend won her first major doubles title at Wimbledon alongside partner Kateřina Siniaková. She also reached the mixed doubles final at the 2024 US Open alongside another boundary breaker, Donald Young, and made a semifinal run at the year-end WTA Finals with Siniaková. Townsend started 2025 off strong when she won her second major doubles title at the Australian Open with Siniaková. The duo continued their streak, winning the Dubai Championships. Townsend then partnered with Evan King for the French Open mixed doubles, with the pair reaching the final. After this string of results, Townsend became the world No. 1 in doubles. She was the first mother to reach No. 1 in the history of the WTA doubles rankings.