Lee Jae-myung, the liberal South Korean politician favoured to become the country's next leader, has overcome a knife attack, martial law and criminal charges on his unexpected path back toward the presidency.

The former Democratic Party chief had led the opposition-controlled parliament’s impeachment of Yoon over the imposition of martial law in December.

South Korea's main opposition party's former leader Lee Jae-myung on Sunday won the party's nomination for the upcoming presidential election, Seoul-based Yonhap News reported. Lee, the front-runner in opinion polls for the June 3 presidential election, won 89.77% of all votes cast in the Democratic Party's primary.