A native of Ōmihachiman, Shiga and graduate of Kyoto University, he was elected to the House of Representatives for the first time in 2000.

[5] Goshi Hosono was a protégé of DPJ Secretary General Azuma Koshiishi, who saw him as a potential future Prime Minister.

However, a significant bloc of ex-DP representatives were barred from running under the Hope ticket by then-party leader Koike.

Several of these representatives then formed the Constitutional Democratic Party (CDP) to house liberal-leaning former DP members.

Hope lost seats and only became the second largest opposition party behind the CDP, which ran a relatively successful campaign despite being hastily established.