Kuncoro played badminton at the 2004 Summer Olympics in men's singles, defeating Roslin Hashim of Malaysia and Jim Ronny Andersen of Norway in the first two rounds.

He became runner-up at the 2007 IBF World Championships after losing to Lin Dan in straight sets with a score of 11–21, 20–22 in Putra Stadium, Bukit Jalil, Malaysia.

On 23 September 2007, Kuncoro won the Chinese Taipei Open Grand Prix Gold after beating Taufik Hidayat in the final round 18–21, 21–6, 21–13.

In June, he won the Indonesia Open Superseries beating Simon Santoso in the final 19–21, 21–14, 21–9 in Istora Senayan, Jakarta.

In September, Kuncoro won the Japan Open Superseries beating Lee Chong Wei from Malaysia in straight sets 21–17, 21–11 in the final.

In 2012, he won the men's singles title at the Thailand Open Grand Prix Gold defeating China's Chen Yuekun in straight games, 21–17, 21–14.

In 2013, he started the year by becoming the semi-finalists in 2013 Korea Open Superseries Premier, beaten by Du Pengyu, 12–21 17–21 and in 2013 Indonesian Masters Grand Prix Gold, giving walkover to Dionysius Hayom Rumbaka.

He also won the 2015 Indonesia International Challenge after defeat the Korean young blood Jeon Hyeok-jin with straight games 22–20, 21–15.

He later won the event after beating China's Lin Dan in the semi-final with score 21–10, 17–21, 22–20,[8][9][10] then South Korea's Son Wan-ho in the final with 21–16, 13–21, 21–14.

It's a reward for his hard work as an independent shuttler after kicked out of the national training camp in mid-2014 because of injuries to his back, waist and wrist over the years.