[1] Soon, he was released and formed the Association of National University Student Representatives (ANUSR) in July.

[1][5] At the NUNDM, he met Kim Geun-tae,[2] the policy director[1] who later be the Chairman of the Uri Party, as well as his wife, Lee Bo-eun.

[5][3][4] He ran as the MP for Guro 1st constituency, but lost[2] to Kim Ki-bae of the Grand National Party (GNP).

He ran again for the presidency of the New Politics Alliance for Democracy in 2015, but came as 3rd and lost behind of Moon Jae-in and Park Jie-won.

[9] Lee was immediately elected as the new parliamentary leader of the party,[8][9] replacing the incumbent Hong Young-pyo.

On 3 July 2020, Lee was nominated as the Minister of Unification,[10] following the resignation of Kim Yeon-chul due to North Korea's destruction of the Inter-Korean Liaison Office in June.

"[12] He also added that there's no centrism in politics, by providing an example: "What is the centre between reducing and increasing the temporary employees?

[5] On 10 May 2019, shortly after being elected as the parliamentary leader, it was reported that Lee denounced civil servants along with Kim Soo-hyun, the policy director of the Blue House.