Kwon played on the Junior Tour from 2011 to 2015 and achieved his best placement there in early 2015 with a combined 46th place in the ranking. Once he was in a Grand Slam tournament: in 2015 at the Australian Open , when he lost early in singles and doubles.
Until the end of his junior career, he played a few tournaments on the third-rate ITF Future Tour , before playing an ATP Challenger Tour tournament in Seoul for the first time in mid-2015 thanks to a wildcard . By the end of the year he had won the first three futures titles, one of which was a doubles, which meant he could not finish the year within the top 1000. In 2016 he won another four futures and finally stood in Gimcheon for the first time in a Challenger semi-finals. From then on, he had collected enough world ranking points to permanently compete in Challengers. In both singles and doubles, he improved greatly in the world rankings and was in the top 300 in singles at the end of the season. In 2017 he played his way through the qualification at the Challenger in Yokohama without losing a set, where he was defeated by Yūichi Sugita . In May he came back to the final in Seoul and lost to Thomas Fabbiano . By the end of the year he was ranked 168th by further passable results. He played in the qualification of two Grand Slam tournaments in Wimbledon and New York and had his Davis Cup premiere for the South Korean Davis Cup team in early 2017 . In 2018 he was able to prevail in the Asia-Pacific Wildcard Playoffs , an elimination for a wildcard at the Australian Open . There he was defeated by Jan-Lennard Struff in three sentences.
In the Davis Cup, in which Kwon has played for South Korea since 2017, he has a score of 3: 3.