Kangnam was born on March 23, 1987 in Tokyo, Japan, and is half-Korean (his mother is Korean) and half-Japanese (his father is Japanese). An only child, he spent most of his childhood in Japan, and also spent some years in Hawaii. In March 2008, Kangnam debuted with the stage name Ya-Cha as a new member of the Japanese band Kick Chop Busters (KCB). However, he left the band in 2010 for unknown reasons, without his parents' knowledge. Kangnam has stated in interviews that his family is wealthy, but he does not receive financial support from them.
Kangnam attended Hawaiian Mission Academy in Honolulu for a period before transferring to another school to finish high school. He then returned to Japan to finish his studies. Kangnam briefly attended Temple University in Philadelphia, Pennsylvania, where he was majoring in Communications, but he left the school to pursue music instead.
In South Korea, Kangnam debuted as a member of M.I.B (band) under the label Jungle Entertainment on October 25, 2011, with the title track "G.D.M" aka "Girls, Dreams, Money." His solo song "Say My Name" was released on October 17, 2011 as part of a spin-off promotion to prove that each member is capable of standing alone. Kangnam is also an accomplished guitarist and pianist.
In 2012, Kangnam appeared in a CF for Epson, an electronics company that specializes in image-related products. Also in 2012, Kangnam took on his first acting role in the tvN sitcom "21st Century Family", and he became the host of the Japanese rendition of Mnet's Jjang.
On the October 3, 2014 episode of I Live Alone Rainbow segment Kangnam revealed that he had only $3 in his bank account. In subsequent Entertainment Relay interviews, he reported that his income had increased significantly, as he became involved with more CFs and variety shows. In October 2014, Kangnam became a permanent cast member on MBC's I Live Alone. In November 2014, Kangnam became an exclusive model for the shoestore ABC Mart, alongside model Nam Joo-hyuk.
Kangnam finally saw the fruit of his labors towards the end of 2014, four years after his debut, hitting a year-end festival stage as an MC, as part of the "Lucky Boys" project for 2014 SBS Gayo Daejun. On the December 26 episode of MBC's I Live Alone, Kangnam opened up about attending year-end festivals for the first time since his debut: "Singers usually appear on TV to sing at the end of each year. Every year, I have been watching TV thinking ‘I’ll do that next year,’ and somehow four years have passed.”
On December 26, 2014, Kangnam released his second solo track, "What Do I Do", which soared to #1 on Daum's real time charts. Kangnam also ranked #1 on several real time searches, including Naver, Melon, Mnet, and more.
In February 2015, he was appointed the honorary ambassador for the fourth KCON music festival and convention for its first time in Japan. Kangnam also performed at the concert on April 22. He has said that his fluency in both languages will allow him to "act as the bridge between the exchange of culture from both countries."
Kangnam released his Japanese solo debut single album Ready to Fly on May 25, 2016 under CJ Victor Entertainment.
On July 14, 2017 Kangnam's agency confirmed he and Uee are dating. They appeared together in a South Korean documentary based reality show Law of the Jungle. On August 1, 2017, the couple was confirmed to have broken up after three months of dating.
For Kangnam's work with M.I.B, see M.I.B's discography.