Subsequently, he was newly appointed as the chairman of the Diet Affairs Committee of the Japan Innovation Party.

[1] On 25 December, Baba officially joined the Initiative from Osaka and became the party's secretary general.

[4] On 30 November 2021, Baba was appointed co-leader and the leader of parliamentary delegate of Nippon Ishin no Kai.

In July 2022, Ichirō Matsui, then leader of Nippon Ishin no Kai, announced his resignation; on 2 August Baba announced his candidacy for party representative following Matsui's resignation;[5] on 27 August Baba received 8,527 of the 10,825 valid votes cast and became the party's new leader that same day.

[6] He stepped down in the wake of the party's poor showing in the 2024 Japanese general election on 27 October and was replaced by Osaka Prefecture governor Hirofumi Yoshimura on 1 December.