The National Team Committee, a KFA advisory body, had been looking for a replacement after sacking Jurgen Klinsmann in the wake of the national side's semi-final exit at the Asian Cup and amid criticism of his leadership.
Hwang, 55, steered the under-23 national team to gold in the 2022 Hangzhou Asian Games, and was a member of the 2002 World Cup squad that reached the semi-finals under Dutch coach Guus Hiddink.
Hwang was the "No. 1 choice" given his experience and he will resume his role with the under-23 team after leading the national side through two 2026 World Cup qualifiers against Thailand in March, said Jung Hae-sung, who heads the committee.
"Our committee, in the meantime, will hold in-depth discussions to appoint a full-time coach, reviewing what kind of football we want to pursue and which style of the coach we need," Jung told a briefing.
The KFA dismissed Klinsmann following South Korea's stumble at the semi-final stage of the Asian Cup, which extended their 64-year wait for a third title and rekindled criticism of the German coach's leadership.
Hwang will double as coach of the national team and also prepare the under-23 squad for the Asian Football Confederation (AFC) Asian Cup to qualify for the 2024 Paris Olympics, starting in April in Qatar.
Hwang will also have to contain infighting in his squad after a well-publicised quarrel between captain Son Heung-min of Tottenham and team-mate Lee Kang-in of Paris St Germain.
