Claire Liu was born and raised in Thousand Oaks, California.
In 2017, Liu was the world No. 1 in the junior rankings, after winning the Wimbledon girls' singles title, and finishing runner-up at the French Open. On September 26, 2022, Claire Liu reached her career-high WTA singles ranking of world No. 73. Liu plays right-handed with a two-handed backhand. She is widely regarded as a WTA rising star with a large amount of potential.