Ju with South Korea at the 2018 FIFA World Cup
|Date of birth||30 October 1990|
|Place of birth||Anyang, Gyeonggi, South Korea|
|Height||1.76 m (5 ft 9 in)|
|2006–2008||Nunggok High School|
|2018–||→ Asan Mugunghwa (army)||40||(3)|
|2011||South Korea U-23||0||(0)|
* Senior club appearances and goals counted for the domestic league only and correct as of 19 August 2019|
‡ National team caps and goals correct as of 11 June 2019
|Revised Romanization||Ju Sejong|
Ju made his league debut for Busan IPark as a substitute in 6–0 defeat away to FC Seoul on 21 July 2012. His first full start came almost two years later in a league match against Gyeongnam on 4 May 2014. Ju scored his first goal for the club in an FA Cup game against Suwon City on 16 July 2014, which IPark went on to win 3–2 after extra time. His first league goal came a month later in a 4–2 victory over Seongnam FC. Ju became a regular starter and key player for IPark in the second half of the 2014 K League 1 season. He finished the season with five assists, the most at the club, and was named in the weekly K League 1 'Best Eleven' on three occasions.
Ju continued to be a regular starter in the 2015 season, as IPark were relegated into the K League 2.
Ju joined FC Seoul on 8 January 2016.
Ju made his debut for the Korean national team on 11 June 2015, appearing as a substitute in a 3–0 victory over UAE. He was later selected in the squad for the East Asian Cup. He made one appearance, starting in the 1–1 draw with Japan, as Korea won the tournament.
- As of 19 August 2019
|South Korea||League||KFA Cup||Play-offs||ACL||Total|
|2012||Busan IPark||K League 1||1||0||0||0||-||-||-||-||1||0|
|2018||Asan Mugunghwa (army)||K League 2||19||1||1||0||-||-||-||-||20||1|
|2019||FC Seoul||K League 1||0||0||-||-||-||-||-||-||0||0|
- As of match played 1 June 2016. South Korea score listed first, score column indicates score after each Ju Se-jong goal.
|1||1 June 2016||Red Bull Arena, Salzburg, Austria||4||Spain||1–5||1–6||Friendly|
- South Korea
- "2018 FIFA World Cup Russia – List of Players" (PDF). FIFA.com. Fédération Internationale de Football Association. 4 June 2018. Retrieved 19 June 2018.
- "BUSAN IPARK FC : GO TOGETHER : ALL FOR BUSAN". busanipark.com. Retrieved 20 June 2016.
- "Revealed: Every World Cup 2018 squad – 23-man & preliminary lists & when will they be announced?". Goal. Retrieved 18 May 2018.
- Ju Se-jong at Soccerway