She is the first woman to hold the post after Kang Kum-sil who was appointed by then-president Roh Moo-hyun, a political mentor of the incumbent Moon Jae-in.

She left her position in protest of government pressure to bring judgements against pro-democracy activists, and joined the opposition National Congress for New Politics.

She crossed regional barriers by being elected as a liberal despite originally hailing from the conservative stronghold of Daegu,[1] and also became the first female member of the National Assembly to have served as a judge—followed by Na Kyung-won in 2004.

[3] Having served in the assembly for seven years, Choo ran for chairman of the Millennium Democratic Party in 2003, coming in second place behind Cho Soon-hyung.

[12] Choo has served as a member of the Assembly's Foreign Affairs and Unification Committee, and in 2003, she was appointed special envoy to the United States on the North Korean nuclear crisis.

[13] Choo visited the United Kingdom in November 2010, giving lectures at Chatham House and the University of Cambridge on future policy in the Korean Peninsula.