Career
He is a forward and currently plays for J. League Division 2 side Thespakusatsu Gunma. Club He played his youth football at Mitsubishi Yowa Club. After graduating from high school in 1997, he joined Urawa.
He made his professional debut on 12 April of that year in the opening league match against Yokohama Marinos at Urawa Komaba Stadium.
Nagai was loaned out to German second division Bundesliga side Karlsruher from 1998 to 1999. He played 21 league games and scored four goals.
In 2003, he took over the number nine jersey from iconic Masahiro Fukuda after the latter retired from the game. He scored a hat trick against Tokyo Verdy 1969 on 21 August 2004.
In the same match, his teammate Koji Yamase also scored three goals.
He was named the player of the tournament. On 7 January 2009, he transferred to Shimizu South-Pulse. International He scored a goal against Costa Rica at the group stage.
The team was eliminated at the quarterfinal.
He also represented Japan at the 1999 Fédération internationale de football association World Youth Championship hosted by Nigeria. He scored a goal in the semi-final against Uruguay and contributed to the team finishing runners-up in the competition.
He made his full international debut for Japan on 21 April 2003 in a friendly against South of Korea at Seoul World Cup Stadium. He is so far capped four times and scored one goal.
Individual Team.