Kang lived in Japan while he received a PhD degree from the University of Tokyo.

[3] On 23 November 2020, President Moon Jae-in appointed Kang Chang-il as the new ambassador to Japan.

[4][5][6] Press Secretary of Japanese MOFA, Tomoyuki Yoshida, revealed on 3 February 2021 that the South Korean side announcement of the appointment was without agrément, and promptly after the announcement, Chief of protocol Atsushi Kaifu had told to embassy of South Korea in Tokyo that it was extremely regrettable to have deviated customary international law.

"[7] An official of the South Korean presidential office said that the appointment of Kang reflects Moon's willingness to improve bilateral relations following Yoshihide Suga's appointment as Prime Minister.

He has relayed Moon's statement that the two governments should prepare solutions to the pending problems through dialogue and that they should cooperate where possible, including on the Tokyo Olympic Games.