NEW South Korean President Lee Jae-myung pledged to “unite the people” in his inauguration speech today, vowing to reopen dialogue with North Korea and strengthen ties with the United States and Japan.

The 61-year-old won last month’s snap election with 49.4 per cent, defeating conservative rival Kim Moon-soo on 41.9 per cent — a rejection of the ruling bloc associated with disgraced former president Yoon Suk Yeol.

Mr Yoon was impeached following his attempt to impose martial law — a move that plunged the country into months of political turmoil and sparked mass protests.

In his inaugural address at the National Assembly, President Lee stated that his administration would respond to the threat of nuclear weapons and aggression from the North with “strong deterrence” through the South Korea-US alliance, while also pledging to restore communication with Pyongyang and seek peace on the Korean peninsula through “talks and co-operation.”

He promised a “pragmatic diplomacy based on national interests,” strengthening trilateral co-operation between Seoul, Washington and Tokyo.

“We will turn the crisis posed by the major shift in global economic and security landscapes into an opportunity to maximise our national interests,” he said.

While Mr Lee had previously faced criticism for being too soft on China and North Korea, he has recently doubled down on his commitment to the US alliance and refrained from any statements that could strain relations with Washington or Tokyo.

The US and Japan welcomed his election, with Japanese Prime Minister Shigeru Ishiba saying he hoped to meet Mr Lee “as early as possible” to deepen bilateral and commercial ties.

The US State Department reiterated its “ironclad commitment” to the alliance with Seoul.

Chinese President Xi Jinping also sent a congratulatory message, expressing a desire to strengthen the partnership between the two countries.

Later today, Mr Lee appointed close ally and veteran lawmaker Kim Min Seok as prime minister, with further cabinet nominations expected in the coming days.

Mr Lee called for national healing following Mr Yoon’s failed martial law manoeuvre, saying: “I will answer the people’s solemn call to let hope bloom over deep and painful wounds.”

He pledged a full investigation into the former president’s actions, describing the martial law attempt as “a rebellion that seized people’s sovereignty with arms.”

On the domestic front, Mr Lee reiterated his commitment to tackling inequality.

“The polarisation fuelled by inequality is now hindering further growth,” he warned.