South Korean President Moon Jae-in on Thursday nominated the head of the Joint Chiefs of Staff as defence minister.
Jeong Kyeong-doo, 58, a former fighter pilot, would take over the ministry as the government seeks to reduce tension and build trust with North Korea, and at a time of uncertainty over relations with main ally the United States.
Jeong, who is set to replace incumbent Song Young-moo, does not need parliament's approval but must attend a hearing and answer legislators' questions.
He would be South Korea's first defence minister with an air force background in 24 years, media reported.
The United States is seeking to press North Korea to give up its nuclear and missile programmes and as part of that effort, US President Donald Trump suspended military exercises with South Korea when he met North Korea's leader Kim Jong Un in a historic June summit.
But with talks between North Korea and the United States stalled, there is speculation the South Korean-U.S. exercises, which the North has long denounced as preparations to invade it, might get going again.
Trump said on Wednesday there was no reason to resume the exercises but US Defense Secretary James Mattis on Tuesday made remarks that were interpreted as hinting the drills could resume.
At the same time, South Korea is making efforts to improve ties between the two Koreas.
The South Korean defence ministry has said it will reduce the number of guard posts and the amount of equipment along the demilitarised zone, on its border with North Korea, under an agreement between Moon and North Korean leader Kim Jong Un at an April summit.
The 1950-1953 Korean War ended with an armistice, not a peace treaty, leaving the countries still technically at war.
Moon and Kim plan to meet for the third time this year in September.
Meanwhile, Moon also named new ministers of labour and industry.
The new labour minister nominee, Lee Jae-kap, must deal with the worst job market since the 2008-2010 financial crisis.
Unemployment is seen as having contributed to a plunge in Moon's approval ratings this month to its lowest ever.