After finishing the university in 1990, he joined Japan Soccer League side Fujita Industries (current Shonan Bellmare).

[1] He made his international debut in a friendly against Argentina on May 31, 1992[1] at the Tokyo National Stadium, the first match under Hans Ooft's reign.

He was suspended for the crucial last match that the Japanese fans now refer to as the Agony of Doha, and watched from the bench a late Iraqi equaliser dashed Japan's hope to qualify for the finals in the USA.

He was unexpectedly promoted to the manager of the club to replace Yusuke Adachi who was sacked only after the team lost to Ehime FC in the opening match of the season.

Yokohama FC, who had been languishing in the bottom half of the standing previous 5 seasons since their accession to J2, won the title and gained the first-ever promotion to J1 League.

Takagi enhanced his squad by recruiting former Japanese internationals Tatsuhiko Kubo and Daisuke Oku (both from Yokohama F. Marinos), and Gilmar Silva (from Tokyo Verdy).

[4] New team leaders Oku and Kubo were sidelined due to injuries and the club was anchored at the bottom of the standing.

Apparently there was a conflict between the management and Takagi as he expressed disgruntlement on Miura's signing quoting that what the club needed at that point was a good defender or forward.

[5] In 2008, Takagi signed with Tokyo Verdy returned to J1 and he served as assistant coach under manager and his former international team mate Tetsuji Hashiratani in 2008.

In 2018, V-Varen gain several players who Takagi's junior at his high school, Yuhei Tokunaga, Hokuto Nakamura and Kenta Tokushige.