Born to a Japanese mother and a Haitian father, Naomi Osaka’s family relocated from Japan to the United States when she was just three years old so she and her sister Mari could pursue tennis. Her father took great inspiration from Venus and Serena Williams’ success and envisioned a future with such opportunities for his daughters. Instead of competing in junior tournaments, Osaka was again inspired by the Williams sisters and began her career on professional satellite tours. Osaka’s professional career began in 2012 when she played her first matches in the ITF Circuit. In 2015, she competed in her first Grand Slam tournaments at Wimbledon and the US Open.

Although she was defeated in the tournaments, Osaka’s career advanced quickly. In 2016 and 2017, she competed in the US Open and reached the round of 32. Also, in 2017, she joined the Japanese Fed Cup Team. In 2018, she defeated Heather Watson 6-2, 6-3 in the tournament's first round. She was a member again in 2020.

Osaka’s career took off in 2018. She finished the year ranked world No. 5 and won her first WTA Tour title and her first Grand Slam tournament title all in one year, with victories at Indian Wells and the US Open. At the US Open, Osaka defeated her childhood idol Serena Williams in the finals 6-2, 6-4. The following year, Osaka kicked off the year with another major trophy, winning the 2019 Australian Open, and was the champion at the Toray Pan Pacific Open and China Open. At the China Open, Osaka defeated Ashleigh Barty in the finals—who was ranked No. 1 at the time— 3-6, 6-3, 6-2. Osaka reached the world No. 1 ranking that year, becoming the first Asian player to have done so. In 2020, she was once again victorious in New York, defeating Victoria Azarenka at the US Open. In doing so, she became the 20th woman to win at least three majors in the Open Era. In 2021, Osaka won a second Australian Open title, defeating Serena Williams in the semifinal and Jennifer Brady in the final, 6-4, 6-3. Later that year, Osaka represented Japan at the Tokyo Olympics, where she became the first tennis player ever to light the Olympic cauldron during the Opening Ceremony. Osaka was eliminated in the third round of competition at the Games. After an injury-plagued 2022, she announced that she would take 2023 off to give birth to her daughter. She returned to the tour in January 2024, winning her first match back at Brisbane. She continued to gain her footing and climbed up in the rankings (from 833 to a high of 56) until a back injury ended her season in October. Osaka started her 2025 season strong by reaching the finals of the Auckland Open but unfortunately had to retire after taking the first set due to an abdominal injury. The same injury forced her to retire during her third-round bout at the 2025 Australian Open.

Osaka has also made a significant impact off the tennis courts. In 2020, she publicly advocated for racial and social justice in the United States to support the Black Lives Matter movement. In 2021, she took an extended break from tennis after the Roland Garros and again after the US Open, citing mental health issues. This resulted in significant public discourse on the topic.

Osaka has become one of the most recognizable athletes in the world today and is the highest-paid female athlete of all time, having earned $57.3 million in endorsements and prize money in 2021, according to Forbes.

Beyond tennis, Osaka is a shrewd businesswoman. In 2021, she started Kinlò, a skin care products company focused on people with melanated or darker skin tones. In May 2022, she announced that she was leaving IMG. With her long-time agent, Stuart Duguid, Osaka started her own company, Evolve, which will manage her business interests.