It was followed by a two-year podium streak, including wins at the prestigious Grand Slam Abu Dhabi and Tokyo.

[5] He attended Kyoto City Hachijo Junior High School, where he began to compete.

[5] Before moving to Korea, An was a student at the University of Tsukuba, where he trained and was teammates with 2015 World Champion Takanori Nagase.

He competed in the −73 kg category, after local lightweight number one Wang Ki-chun missed the tournament.

[12] An won his first IJF circuit title at the 2014 Grand Prix in Jeju, beating established opponents such as 2008 European Champion Dirk Van Tichelt in the semi-finals, and future European Champion Sagi Muki in the finals, both by ippon.

An again had a fairly successful outing at the Grand Prix in Düsseldorf, where he was guaranteed a medal by beating Muki by ippon in the quarter-finals.

An continued his medal-winning streak at the European Open in Warsaw, reaching the final after winning all his fights en-route by ippon.

– An in 2014 on succeeding Wang as Korea's top lightweight as the latter ascended to half-lightweight An competed in his second world championships in Astana, Kazakhstan, and reached the semi-final.

Ono sealed his win with an ushiro goshi, ending An's hopes of becoming Korea's third lightweight world champion, after Lee Won-hee and Wang.

He then went on to win by shido against Ganbataar in the bronze-medal contest, becoming one of South Korea's five individual medalists at the championships.

An's opponent in the team final was double world champion and the 2015 silver medalist Riki Nakaya.

An won his first Grand Slam at Abu Dhabi, winning all his fights by ippon with the exception of the quarter-final against half-lightweight Olympic champion Lasha Shavdatuashvili.

An had a re-match with van Tichelt again in the final for the second year running at the Grand Slam in Jeju.

– An on his ambitions at the 2016 Olympics At his first outing to one of the IJF circuit's most prestigious events, An managed to win his second Grand Slam title.

"[16] An again faced his rival Ono in the semi-final at the Grand Prix in Düsseldorf, and lost for the fourth time.

In 2021, he won the gold medal in his event at the 2021 Judo World Masters held in Doha, Qatar.