Intelligence agency chief nominee Lee Byung-kee is a member of President Park Geun-hye's senior mentors' circle, with vast experience in politics and security affairs.

Lee, currently South Korea's ambassador to Japan, has frequently been cited as one of the core senior mentors to Park since her first presidential bid in 2007.

The 67-year-old nominee started his professional career as a diplomat after passing the state exam for diplomats in 1974. He soon moved to politics to serve as a chief protocol secretary for former President Roh Tae-woo, as well as a vice chief of what is now the National Intelligence Service in the 1990s.

Lee has also closely assisted Park, having served as the vice chief of the election strategy committee for her botched presidential bid in 2007. Park was defeated by Lee Myung-bak in the then main opposition Grand National Party's race to win the party ticket for the presidential election.

Lee later became a senior adviser at the Youido Institute, the party's think tank, in 2013 when Park successfully ran for the presidency.

He then returned to the diplomatic world after being named South Korea's chief envoy to Japan, one of the most coveted diplomatic seats.

He is widely known for his prudent behavior and keen political sense, and Park reportedly puts her full confidence in him.

The nomination requires the parliament's approval. (Yonhap)