De Groot was born with unequal leg length and began her wheelchair tennis career at the age of seven. She started playing on the ITF Wheelchair Tennis Tour in 2009 as a junior player. During her time with the ITF, De Groot won the Cruyff Foundation Junior Masters in 2013 in singles and doubles. The following year, she won the 2014 Junior Masters in doubles. De Groot made her first Grand Slam appearance at the 2017 Australian Open. After placing in the quarterfinals at the Australian Open and the 2017 French Open, de Groot won her first Grand Slam title at the 2017 Wimbledon Championships. She ended the 2017 Grand Slam tournaments with a finals finish at the 2017 US Open. At the start of 2018, she won the 2018 Australian Open and appeared at the final of the 2018 French Open. For the remaining Grand Slams of 2018, De Groot won the women's singles division at the 2018 Wimbledon Championships and her first US Open singles title at the 2018 US Open. In 2019, de Groot rewon the Australian Open title in singles competition at the 2019 Australian Open. At the 2019 French Open, de Groot completed her career Grand Slam when she won her first French Open singles title. Her French Open title also made de Groot the first wheelchair tennis player to complete a Non-calendar year Grand Slam. At the 2019 Wimbledon Championships, de Groot ended her back to back singles wins when she was defeated by Aniek van Koot in the final. In doubles, De Groot was a runner up in the 2017 Australian, French and Wimbledon championships. After winning her first doubles title at the 2017 US Open, she lost at the 2018 Australian Open and co-won the doubles event at the 2018 French Open. De Groot became the first woman in wheelchair tennis to win both the women's singles and doubles events at Wimbledon in July 2018. She won her second US Open doubles title at the 2018 US Open alongside Yui Kamiji. At the 2019 Australian Open, De Groot won her first Australian doubles title with Aniek van Koot alongside her singles title in January 2019. At the following Grand Slams, De Groot and Van Koot won the 2019 doubles titles at the French Open and Wimbledon. Outside of the Grand Slam tournaments, De Groot competed at the 2016 Summer Paralympics in singles and doubles competitions. While De Groot did not medal in singles, she won a silver medal in women's doubles. In Masters competitions, De Groot won the 2017 and 2018 Wheelchair Tennis Masters in women's singles. Competing in doubles, she won the 2016 Wheelchair Doubles Masters with Lucy Shuker and the 2017 Wheelchair Doubles Masters alongside Marjolein Buis. She has also appeared at the BNP Paribas World Team Cup in consecutive years from 2011 to 2019. At the World Team Cup, De Groot started as a junior in 2011 before competing a world team competitor in 2012.
