Fujii started judo at the age of three due to her father's influence and continued competing at Shukugawa Gakuin Junior High School and Kokushikan University.

[2] Fujii was trained in MMA and catch wrestling by Shooto veteran Hiroyuki Abe and Josh Barnett, a former UFC Heavyweight Champion and King of Pancrase.

[citation needed] In 2005, the first year women competed at the ADCC World Championships, Fujii won bronze in the -60 kg division.

[6] Fujii was also a multi-time contestant on the seasonal Japanese obstacle course television show Sasuke (Ninja Warrior), but never made it past the first stage.

[citation needed] Fujii debuted in mixed martial arts on August 5, 2004 and defeated Yumi Matsumoto by submission in 40 seconds.

Further wins over Ana Michelle Tavares, Misaki Takimoto, Keiko "Tama Chan" Tamai and Masako Yoshida established Fujii as one of the top female fighters in the world and she became a staple of Shooto and Smackgirl events.

[7] On August 24, 2007, Fujii defeated highly touted American Lisa Ellis by first-round submission at a BodogFight event in Vancouver, British Columbia.

After submitting Won Bun Chu in less than one minute at Shooto: "Tradition Final" in May 2009, Fujii returned to Jewels and defeated rising Japanese contender Saori Ishioka late in the second round.

She defeated veteran striker "Windy" Tomomi Sunaba by first-round armbar at Shooto: "Revolutionary Exchanges 3" on November 23, 2009.

[27] Fujii faced Karla Benitez at DREAM – Fight For Japan: Genki Desu Ka Omisoka 2011 on December 31, 2011.

[36][37] In her retirement bout, she faced Jessica Aguilar in a rematch at Vale Tudo Japan 3rd on October 5 in Tokyo.