In 2003, he led the Hanshin Tigers to their first Central League pennant in 18 years before retiring for health reasons.

Hoshino's reputation as a hot-headed leader[3] began in his years at Meiji University, when he and other members of the baseball team banded together to break down a barricade set up around the school by a student protest group.

Hoshino was drafted in the first round by the Chunichi Dragons in 1968, led by manager Shigeru Mizuhara.

Hoshino worked as a commentator for NHK after retiring, and his popularity with both fans and players called him back to the Chunichi Dragons as a manager in 1987.

In 2002, Hoshino was called to take over as manager of the Hanshin Tigers, who had been in last place for the last four years under Katsuya Nomura.

He raised the team to fourth place in his first year, and made huge cuts during the off-season while recruiting free agents like Tomoaki Kanemoto and Hideki Irabu.

However, he frequently fell ill during games in 2003, often leaving the head coach to manage the team while he sat quietly on the bench.

He stepped down after the 2003 Japanese championship series for health reasons, allegedly due to high blood pressure and heart arrhythmia, but was the assistant senior director of the Hanshin Tigers until 2010.