He was traded to the Osaka Kintetsu Buffaloes in 2004 after pitching in a career-high 62 games in 2003 with a 4.50 ERA as a reliever in his final year with the BayStars.

However, the Buffaloes team was disbanded during the off-season, and Fukumori was handed over to the newly created Tohoku Rakuten Golden Eagles in a distribution draft.

He recorded the first save in history for the Eagles on April 13 against the Fukuoka SoftBank Hawks, and was the only pitcher to not let up a run in the team's epic 0-26 loss to the Chiba Lotte Marines in the second game of the season.

Fukumori was relegated to setup duty at the start of 2006 in favor of Shinichiro Koyama, but returned to his closing role early in the year, pitching 26 straight innings without giving up a run in the first half of the season.

On June 13, 2009, the Texas Rangers released Fukumori so that he could sign with the Tohoku Rakuten Golden Eagles of the Japanese Pacific League.