Born in Togliatty, Russia, Kasatkina made her WTA qualifying debut in 2013 and her main draw debut as wild card in 2014 (l. Riske 1r) always in Moscow. In 2015, in Bad Gastein (as qualifier) she reached for the first time the quarter-finals. That year in Moscow she recorded the first Top 20 win over No.14 Suárez Navarro in the quarter-finals and reached her first WTA semifinal (l. Pavlyuchenkova).
In 2016 she achieved her second WTA semifinal in St Petersburg (l. eventual R‐Up Bencic) and the quarterfinals stage in Indian Wells (l. Ka.Pliskova), Charleston (l. eventual champion Stephens having held MPs), Montréal (l. Kerber), Rio Olympics (l. Keys) and Moscow (l. Goerges). At Us Open, she also made the R16, her best Grand Slam result. Kasatkina ended 2016 at career‐best No.27.
The Russian opened the 2017 season with a quarter-final showing at Sydney where she defeated Kerber and became the sixth teenager to beat a world No.1. She began clay court swing by capturing first WTA singles title in debut final at Charleston defeating Ostapenko in the first all‐teenage final on tour since 2009 Linz (Wickmayer d. Kvitova). She became sixth teenager to be crowned champion there, joining Evert (1974), Austin (1979, 1980), Graf (1986, 1987, 1989), Hingis (1997, 1999) and Lisicki (2009). In her last tournament of the year, Kasatkina lost to Gorges in the Moscow final.