Simona Halep was born in Constanța, Romania, on 27 September 1991. She started playing at four, moved to Bucharest at 16 and in 2008 won the French Open junior title, becoming the world's top-ranked junior. At 1.68 m she was small for the modern women's game; she made up for it with speed and anticipation, and she was described as an aggressive baseliner and one of the best returners on tour.
She reached her first major final at the 2014 French Open, losing to Maria Sharapova, and later that year she lost the WTA Finals title match to Serena Williams. From January 2014 she stayed in the top 10 for 373 consecutive weeks, until August 2021. Coached by Darren Cahill from 2016, she lost the 2017 French Open final to Jeļena Ostapenko, but on 9 October 2017 she became world No. 1 and finished both 2017 and 2018 at the top, 64 weeks in all.
Her major titles came in 2018 and 2019. After losing the 2018 Australian Open final to Caroline Wozniacki, she won the French Open that June, beating Sloane Stephens after trailing by a set and a break. In the 2019 Wimbledon final she beat Serena Williams, allowing her only two games in each set. Clay was her favourite surface, and she won majors on both clay and grass.
In 2022 she won her 24th title in Toronto, but a test at that year's US Open was positive for roxadustat and was provisionally suspended from 7 October 2022. The original ban was four years. In 2024 the Court of Arbitration for Sport found that a contaminated supplement was the likely cause and reduced it to nine months, already served. She returned at the 2024 Miami Open on a wild card, and after losing in the first round of the 2025 Transylvania Open she announced her retirement on 4 February 2025. Wikipedia counts 24 singles titles in its summary and 25 in its introduction.