Svetlana Kuznetsova was born in Leningrad on 27 June 1985 into a family of cyclists. Her father Aleksandr coached Olympic and world cycling champions, her mother Galina Tsareva was a six-time world champion, and her brother Nikolay won an Olympic silver medal in Atlanta in 1996. She chose tennis instead, starting at seven, and at 13 she moved to Spain for better training.
Her breakthrough came in 2004. That summer she won the US Open, beating her compatriot Elena Dementieva in the final, and in June she had already reached No. 3 in the doubles rankings. She also helped Russia win the Fed Cup that year, the first of three titles, followed by 2007 and 2008. In 2005 she won the Australian Open doubles with Alicia Molik.
She reached two more major singles finals and lost both to Justine Henin: the 2006 French Open and the 2007 US Open. In September 2007 she rose to world No. 2, her career high; Wikipedia gives both 9 and 10 September for the date. Her second major title came at the 2009 French Open, where she beat another compatriot, Dinara Safina, in the final.
In 2011 at the Australian Open she lost to Francesca Schiavone 6–4, 1–6, 16–14 in the longest recorded women's Grand Slam match of the Open Era. In 2012 she won a second Australian Open doubles title, with Vera Zvonareva.
Kuznetsova won 18 singles titles and 16 doubles titles, with a 670–348 singles record and more than 25.8 million US dollars in prize money. Wikipedia dates her retirement to 2021, and she is on the ballot for the International Tennis Hall of Fame class of 2027.