Kurumi Nara began playing tennis at the age of three. As a freshman at Osaka Sangyo's high school in 2007, Nara won the Under-18 singles title at the All Japan Junior Tennis Championships. That year, partnering Misaki Doi, at Wimbledon they became the second Japanese women's doubles pair to reach the finals of a Grand Slam juniors event since Yuka Yoshida and Hiroko Mochizuki at the 1993 US Open. The Nara–Doi team went on to reach the junior doubles semifinals at the 2007 US Open and Wimbledon 2008. In 2007, she became the first Japanese woman to win the Osaka Mayor's Cup since Ryōko Fuda in 2002.
Nara played her first WTA qualifying in 2008 at Tokyo [PPO] as a wild-card (l. Arn) and made her main draw at 2009 Osaka, always as a wild-card (l. Bartoli).
She made her Grand Slam debut at 2010 Roland Garros, coming through qualifying before losing to Parra Santonja in the first-round.
In 2013 she posted her first Top 10 finish at No.76, after moving for the first time to the third-round at Grand Slam level at Us Open. In 2014 she won her career-first WTA title in Rio de Janeiro (d. Koukalova) and was also runner-up in Washington (l. Kuznetsova in F), where she lost the first of her two doubles final partnering Kuwata. At the end of the season, she was ranked at No.44 for her first Top 50 finish.
Nara managed to finish into the Top 100 in 2015 (No.83), reaching the semifinals in Hobart and two quartter-finals in Kuala Lumpur and Nürnberg, and 2016 (No.75) after three quarter-finals in Kaohsiung (l. to Doi), Nanchang (l. to Duan) and Tokyo [Japan Open] (l. to Cepelova).
She ended the 2017 season ranked No.101, her first end-of-year ranking outside the Top 100 since 2012. Her best results included a third-round exit at the US Open (l. Safarova), tying her career best result at a major. She also reached three semifinals at ITF level in Tokyo, Suzhou and Gifu. In 2018, there, she won the title at the $80k tournament, her first at this level since February 2014 in Rio de Janeiro.