Ajla Tomljanovic was born to Croatian father Ratko, a former handball player who won the 1992 and 1993 handball European Cup, and Bosniak mother Emina. She started playing tennis at age 7 introduced by the sister and met as a child Chris Evert in what she considers her best tennis memory.
She made her pro debut on ITF Circuit in Croatia in 2007, and two years ago at Indian Wells, she lived her first main draw appearance at WTA level, losing to Angela Haynes. As a junior, she achieved the career-high ranking of No.4 in singles and No.4 in doubles, as she won the junior doubles crown in Australia in 2009 (w/McHale)and in that same 2009 she was a member of Croatia’s victorious junior Fed Cup team.
She improved her ranking from No.453 to No.78 in 2013 season, after clinching the quarter-finals in Québec City and reached four times the fourth round: it was the biggest jump of any player in Top 100 that season.
In 2014, Tomljanovic announced she would switch nationalities and start representing Australia and did so for the first time at 2014 US Open. At Roland Garros, however, she had reached the first Grand Slam fourth-round in her career. In her run, she upset 2010 French Open Champion Francesca Schiavone in the 1st round, the 32nd seed Elena Vesnina in the next match and then 3rd seed Agnieszka Radwańska. She moved to Brisbane in November 2014 with Australian residency.
She ended 2015 at No.66 for her third consecutive Top 100 finish. That year, Tomljanovic reached the first WTA final of her career finishing runner-up in Pattaya City (l. Hantuchova): after that run, she made her Top 50 debut. She also clinched the first Premier-level quarter-final of her career in Stanford (l. No.11 Karolina Pliskova). Other notable results in 2015 were the semifinals run at Tokyo [Japan Open] (l. eventual champion Wickmayer) and the quarter-finals in Strasbourg (l. eventual champion Stosur).
Tomljanovic finished 2016 season at No.930 after playing only two tournaments all year, at Brisbane and Australian Open. Then, she underwent a shoulder surgery that forced her sidelined for the rest of the season.
She started the 2017 season in Acapulco, advancing to the second round after beating Bouchard in her first main draw win since 2015 Tokyo [Japan Open]. She defeated No.13 Vesnina on her way to a third-round in Miami (l. Safarova). On ITF Circuit, she finished runner-up in the final tournament of the year at $100k event in Dubai (l. Bencic) in December. Previously, she was losing finalist at $60k tournament in Sacramento (l. Anisimova) and $80k event in Waco (l. Townsend).
Tomljanovic began the 2018 campaign reaching back-to-back SFs at the WTA 125K Series events at Newport Beach (l. eventual champion Collins) and Indian Wells (l. K.Bondarenko). In Monterrey, she made her first WTA quarter-finals appearance since 2015 (Tokyo [Japan Open]) before falling to the eventual champion, Muguruza. She then reached her second career WTA singles final at Rabat (l. Mertens).