The 26-year-old defeated countryman Kim Tae-hoon (72) and India's Jyoti Randhawa, who registered a 67 for his best score of the week, with a winning total of 12-under-par 276 at the Haesley Nine Bridges Golf Club.
Current Asian Tour No.1 Kiradech Aphibarnrat of Thailand, who was three shots off the lead at the start of the final round, carded a 73 to settle tie share fourth place with Jason Knutzon (69) of the United States and Baek Seuk-hyun (69) of Korea.
Kang's lead never looked threatened after he shot four straight birdies starting from the third hole. He bogeyed holes eight and 16 but was still comfortably in charge. He is the only other player apart from K.J. Choi to win the CJ Invitational which has been staged on the Asian Tour Schedule since 2011. Choi, who won in 2011 and 2012, shot a 73 to finish in tied 21st position.
"I can't believe that I won. I felt very comfortable after nine holes. I was looking at the scores and I saw that I had a big lead so I was able to play it safe and try to give myself chances. It has been quite a while since I last won so this is a great feeling," said Kang.
The slightly built Korean has been playing in the United States in the last three years, including a year on the PGA Tour in 2011.
Randhawa, the 2002 Asian Tour Order of Merit leader, earned his best result since his last victory in 2009 after hitting six birdies against one bogey.
"Start with a bang and end with a bang but I have no idea what happened in between. I had a good ball striking day. I felt my best out there and I'll take the positives out of this round until the end of the year," said Randhawa, an eight-time Asian Tour winner.
276 - KANG Sung-hoon (KOR) 68-69-69-70.
281 - Jyoti RANDHAWA (IND) 67-74-73-67, KIM Tae-hoon (KOR) 66-69-74-72.
282 - Jason KNUTZON (USA) 72-71-70-69, BAEK Seuk-hyun (KOR) 70-73-70-69, Kiradech APHIBARNRAT (THA) 66-71-72-73.
283 - KIM Gi-whan (KOR) 69-72-72-70, MAENG Dong-seop (KOR) 69-70-70-74.
284 - Panuphol PITTAYARAT (THA) 70-77-69-68, Zaw MOE (MYN) 70-74-71-69.
285 - LEE Kyoung-hoon (KOR) 69-77-71-68, Rikard KARLBERG (SWE) 69-68-71-77.
286 - Berry HENSON (USA) 69-74-75-68, PARK Ju-hyuk (KOR) 74-68-72-72, Unho PARK (AUS) 70-76-68-72, Jbe KRUGER (RSA) 71-72-70-73.
287 - KANG Wook-soon (KOR) 75-72-71-69, KIM Hyung-tae 404 (KOR) 70-76-71-70, HWANG Inn-choon (KOR) 72-73-70-72, Anirban LAHIRI (IND) 69-76-69-73.
--IANS (Posted on 13-10-2013)