Barty then won her first Premier Mandatory and major tournament titles in doubles in 2018 before accomplishing the same feat in singles in 2019, highlighted by her victory at the 2019 French Open.

Barty also led Australia to a runner-up finish at the 2019 Fed Cup and won a bronze medal in mixed doubles at the Tokyo Olympics in 2021.

Despite her short stature for a professional tennis player, she was an excellent server, regularly ranking among the WTA Tour's leaders in aces and percentage of service points won.

[19] Joyce remarked that he did not typically train children as young as Barty, but made an exception because of her excellent hand-eye coordination and high level of focus.

"[15] As a child, Barty also practised at home, remembering, "I used to hit the ball against [the wall exterior to our living room] every day after school, for hours on end."

She started playing low-level events on the ITF Junior Circuit in 2009 at the age of 13 and won her first title at the Grade-4 Australian International before turning 14.

Barty continued to play only in tournaments below the higher tiers until the end of 2010, compiling a record of 24–2 in her five events that season while also capturing a Grade 2 title in Thailand.

[23][28][29] In the last major of the year Barty produced another strong singles result, losing to top seed Caroline Garcia in the semifinals of the US Open.

[38][39][40] The following week, Barty made her singles debut as a wildcard at the Hobart International, losing her opening round match to Bethanie Mattek-Sands.

[43][44] Later in the year, Barty also received wildcards into the main draws of the French Open and Wimbledon, but lost her opening-round matches to Petra Kvitová and Roberta Vinci, respectively, both of whom were seeded.

[60] Without Dellacqua as her partner, Barty had also made two more tour-level semifinals earlier in the year, including at the Premier-level Charleston Open with Anastasia Rodionova.

[48] Barty became interested in potentially playing cricket after meeting with the Australian women's national team in early 2015 to discuss her experience as a professional athlete.

[71] Western Suburbs ultimately won the league's grand final, with Barty ending up the team's top scorer in the match after hitting 37 from 39 balls.

[72] After Barty's performance in her second game with Western Suburbs, she also signed with the Heat for the inaugural Women's Big Bash League (WBBL) Twenty20 season.

[71] Barty announced her return to professional tennis in February a few weeks after the end of the WBBL season,[76] and began working with Craig Tyzzer as her coach.

[87][88] Barty continued to climb the rankings after a quarterfinal showing at the Internationaux de Strasbourg on clay, where she lost to compatriot Daria Gavrilova, and a runner-up at Birmingham on grass, her best result at a Premier tournament.

[98][48] Barty had a strong start to the 2018 season, reaching the final of the Sydney International[99] and being seeded at a Grand Slam tournament for the first time at the Australian Open, but was upset in the third round by Naomi Osaka.

[100] Barty's best result during the clay-court season was at the Internationaux de Strasbourg, where she was the top seed at a WTA Tour singles event for the first time.

[101][102] The following week at the French Open, Barty had another tough draw at a Grand Slam event and was defeated by Serena Williams in the second round, despite winning the first set.

[112] Barty then defeated defending champion Julia Görges and home favourite Wang Qiang to win the biggest title of her career and end the season at a career-high ranking of No.

In the semifinals, the pair defeated the top seeded team of Barbora Krejčíková and Kateřina Siniaková, who were the reigning French Open and Wimbledon champions.

[139] She closed out the clay court season by winning her first Grand Slam singles title at the French Open, defeating Markéta Vondroušová in the final, dropping just four games.

With the title, she won $4.42 million, the largest amount of prize money at a single men's or women's tournament in tennis history to date.

Nevertheless, Barty became the first Australian woman to reach the semifinals since Wendy Turnbull in 1984 and picked up her first top ten win at a major (quarterfinals over Kvitová).

After taking a rest break, Barty returned to court making her debut at the Qatar Open, the first Premier 5 tournament of the year, where she lost to Kvitová in the semifinals.

[158] After an 11-month hiatus due to the COVID-19 pandemic, Barty returned to the tennis courts at the Yarra Valley Classic, one of the three lead-up tournaments to the Australian Open, where she defeated Garbiñe Muguruza in two tight sets in the final.

[159] After this, Barty entered the Australian Open as the first seed in the draw for the second consecutive year and projected as one of the favourites to claim the title, but was knocked out by Karolína Muchová in the quarterfinals.

In an interview with her friend and former doubles partner, Casey Dellacqua, Barty said, "I don't have the physical drive, the emotional want and everything it takes to challenge yourself at the very top of the level any more.

In their February tie against Ukraine, she won both of her singles matches as well as the deciding doubles rubber with Dellacqua to carry her team into the World Group playoffs.

[180][123] In the following round, Barty won both of her singles matches against the Netherlands to help Australia win the tie 4–1 and advance back into the top-tier World Group in 2019 for the first time in four years.