Haas started playing tennis at the age of five, her preferred surface is the hard court. In 2012 she won her first singles title and in 2013 her first double title at the ITF Women's Circuit . So far she has 16 single and two double titles. In 2014 she was placed in the top 300 of the WTA world rankings for the first time . From 2012 to 2014 she played for the TC Blau-Weiss Halle in the 2nd German Bundesliga .
In September 2015, she won her first title in the $ 25,000 category, setting a new career high in the individual world rankings. In September 2016, after her first successful qualification for the main draw of a Grand Slam tournament at the US Open , she improved to 134th place.Haas celebrated her greatest success so far on the WTA Tour in October 2019 at the WTA tournament in Linz in doubles, where they reached the final together with the Swiss Xenia Knoll , which they lost against Barbora Krejčíková and Kateřina Siniaková 4-6, 3-6 .
In February 2015, she had her first appearances in the Fed Cup against Latvia and she was also able to celebrate her first victory (6: 0, 2: 6, 6: 0 over Diāna Marcinkēviča ). Your Fed Cup record shows so far 13 wins and 7 losses.