He was scheduled to manage the Japanese national team for the 2004 Athens Olympics, but he suffered a stroke shortly before and was hospitalized.

He recovered from his stroke, appearing at a baseball game in the Tokyo Dome in 2005, and in a television commercial in 2006, with his son, Kazushige.

After graduating from his local high school in Chiba, he entered Rikkyo University, and became the team's regular third baseman.

He won the batting title for two consecutive years in the Tokyo Big6 Baseball League, and was given the Best Nine Award five seasons in a row at third base.

The Giants won the league championship nine years in a row from 1965–1973, and Oh and Nagashima dominated the batting titles during this period.

Nagashima won only two Golden Glove awards, because the title was established in Japan late during his career, in 1972.

Nagashima was a flashy fielder, making extravagant leaps and dashes to field even the most routine ground ball.

The team attempted to revive him by giving him more at-bats, but Nagashima no longer had the success he had shown during his younger years.

In the off-season of the same year, Nagashima and the Giants were involved in a huge controversy concerning the drafting of pitcher Suguru Egawa.

In the 1992 draft, he won the lottery to sign Hideki Matsui, who would become the new star of the Giants during Nagashima's second run as manager.

Nagashima's Giants won the Central League Pennant in 1994, 1996 and 2000, winning the Japan Series in 1994 and 2000, and he managed the team until 2001.

The team (consisting entirely of players from the Japanese professional leagues) beat China, Taiwan, and Korea to win the Asia tournament in November 2003, but Nagashima suffered a stroke in March 2004, and was unable to travel to the Athens Olympics.