- Bats Left, Throws Left
- Height 5' 9", Weight 190 lb.
- School Waseda University
- High School Imabari Nishi High School
- Born May 12, 1977 in Iyo, Ehime Prefecture, Japan
Fujii began playing baseball in Little League in the second grade. While in high school, he was his team's ace and cleanup hitter. In 1995, he played in the spring Koshien Tournament.
While in college, he went 24-10 with a 1.91 ERA. He was named to a Tokyo Big Six University League Best Nine team as a sophomore. He was drafted in the second round in 1999.
He began his NBP career in 2000, pitching for the Yakult Swallows and going 1-0 with a 4.73 ERA in 31 relief appearances. The following year, he became a starter and went 14-8 with a 3.17 ERA in 27 games, leading the league in wins and tying Darrell May for the lead in home runs allowed. In that year's Nippon Series, he started the second game. He also pitched in the 2001 Baseball World Cup in 2001. In 2002, he was the team's Opening Day starter. That year, he went 10-9 with a 3.08 ERA in 28 games. In 2003, he pitched only one game, posting a 3.38 ERA in 2 2/3 innings. He then underwent Tommy John surgery.
He returned in 2004 and went 4-6 with a 5.51 ERA in 15 starts, missing much of the season after suffering a knee ligament injury. In 2005, he went 10-12 with a 3.43 ERA, tying Yuji Yoshimi for the Central League lead in home runs allowed, with 25. On April 6, he teamed with Ryota Igarashi andHirotoshi Ishii to strike out 19 batters, a Nippon Pro Baseball record. On May 5, he was involved in an ugly incident involving famed Chunichi Dragons' slugger Tyrone Woods. After throwing a pitch by the head of Woods' head, Woods became angered, charged the mound and punched Fujii. Woods was suspended 10 games for the incident and fined 500,000 Yen. In 2006, he went 7-8 with a 4.41 ERA in 27 games (20 starts). 2007 was his final season with the Swallows - that year, he went 7-10 with a 5.05 ERA in 25 games.
In January 2008, Fujii was traded to the Nippon Ham Fighters with Hajime Miki and Yataro Sakamoto for Keizo Kawashima, Yoshitaka Hashimoto and Takehiko Oshimoto. He went 3-8 with a 3.25 ERA for them that season. He became a free-agent following the season and was signed by the Giants. He went 7-5 with a 3.53 ERA for them in 2009, starting the fifth game of that year's Nippon Series, and in 2010, he went 7-3 with a 3.76 ERA in 23 games.