[3] Kim Kyu Jong was born on February 24, 1987, in Jeonju, North Jeolla Province, South Korea.

[11][12] Kim, along with the members of SS501, except for Heo Young-Saeng who was recovering from surgery, lent their voices to the Korean version of the 2006 animated film Pi's Story.

[13] On August 21, 2006, when fellow member Heo Young-Saeng left the radio programme SS501's Youngstreet on Seoul Broadcasting System (SBS) due to a throat condition requiring laryngeal surgery, he took over being the DJ,[14] and continued to host the programme with fellow member Park Jung-min.

[21] However, they stopped their activities as a group for a period of time as Park Jung-Min and Kim Hyun-Joong were given solo projects for Grease musical[24] and Boys Over Flowers series[25] respectively.

[26] They also contributed to the Boys Over Flowers soundtrack with "내 머리가 나빠서" (Because I'm Stupid),[27] and appeared as a cameo in episode four, performing their track "U R Man".

[37] Later on, Kim and Heo held a joint fan meeting, Kyu Jong & Young Saeng Story In Seoul on December 4, which continued in Hong Kong, Japan and countries across Asia.

[2] He performed this musical at Minami-za in Kyoto, Japan from June 11 to July 1,[41] and subsequently in Seoul, Korea in September 2011.

[44] In October 2011, Kim Kyu Jong was cast in the 36-part weekend drama, Saving Madame Go Bong Shil on cable channel CSTV.

[46] On November 9, 2011, he performed along with other Korean and Japanese artists at the Seoul Tokyo Music Festival 2011 at Saitama Super Arena, Japan.

[48] On June 3, he held his farewell fan meeting, Thank U ThanKYU with Triple S at Yonsei University in Sinchon-dong, Seoul.

[53] During SS501's eighth anniversary, Kim, along with the SS501 members posted one video of them celebrating and greeting their fans on each of their own official YouTube accounts.

[59] At around 9:30 to 10 am,[60] he arrived at the military manpower office in Jeonbuk, Jeonju, and he was welcomed by the fans and press who waited for hours.

[61] Kim came back as part of KBSN's special project drama ‘S.O.S Please Save Me’ for the role of Park JungJun.