Hsieh is married to Yu Fang-chih (游芳枝); together, they have a daughter and an adopted son.
Hsieh was forced to resign as premier in the aftermath of the 2005 "Three-in-One" elections in which the KMT defeated the DPP in a landslide.
As the DPP candidate for the 2006 Taipei Mayoral election, Hsieh lost the race to KMT candidate Hau Lung-pin by 166,216 votes (12.92%).
In February 2007, he led the Taiwanese delegation to the 55th annual United States National Prayer Breakfast in Washington DC, hosted by US Congressional Committee with dignitaries including President George W. Bush.
Hsieh has been granted many Taiwanese aboriginal names by many tribe leaders during his visits to the tribes, such as Tin Kei in Amis, V'oyu in Tsou, Hayung in Atayal, and Shaman Manida in Tao.
Regarding Ma Ying-jeou's idea of a "cross-strait common market," Hsieh states that if Taiwan only focuses on the economy, it will end up like Hong Kong and Macau, whose only goal in life is to make money. Hsieh believes that improving the economy is as important as preserving national dignity, and that the goal of economic development is more than just making money, but it is also improving the happiness of people.
Following the DPP's poor performance in the 2008 Legislative election, Hsieh replaced Chen Shui-bian as chairman of the DPP.
In January 2008, Hsieh accused candidate Ma Ying-Jeou of having a United States green card. After investigations, it was revealed that one of Ma's sisters and one of his daughters are both US citizens. Hsieh also publicly expressed that if Ma shows him the official document of his withdrawal of the green card, Hsieh would withdraw from the election. Had Hsieh been elected president, he would have been the first and only president to have adopted a Western first name.
On March 22, 2008, Hsieh lost to the Kuomintang (KMT) candidate Ma Ying-jeou, ending eight years of DPP rule. Hsieh had 5,445,239 votes, 41.55%; against Ma's 7,658,724, 58.45%.
The election was devastating to Hsieh and the DPP because he lost by a wider-than-expected margin of 17%. Hsieh had stated that if he lost this election, he would quit politics for good. He resigned from the DPP chairmanship in order to take responsibility for the election, a tradition in the DPP party. Tsai Ing-wen was nominated and subsequently won the chairmanship.
| Party | Candidate | Votes | Percentage | ||
|---|---|---|---|---|---|
| President | Vice president | ||||
| Kuomintang | Ma Ying-Jeou | Vincent Siew | 7,659,014 | 58.45% | |
| Democratic Progressive Party | Frank Hsieh | Su Tseng-Chang | 5,444,949 | 41.55% | |
| Total | 13,103,963 | 100.00% | |||
Although Hsieh had promised to retire from politics if he were defeated, he has not stopped addressing political issues and has recently shown signs that he is not leaving the political arena, perhaps aspiring to run in another presidential race. When asked about his vow to quit politics if he lost his presidential bid in early 2008, Hsieh responded that he was merely exaggerating for effect on the campaign trail.
Hsieh has also recently shown bitterness for losing to Ma Ying-Jeou, whilst the media has shown Ma with less-than-impressive early approval ratings from citizens.