[13][14][15][16] The same year, Kwak featured in the KBS period drama Inspiring Generation playing the younger version of Kim Hyun-joong's character.

[17] His portrayal of a boy who struggled as the head of the family from an early age to fill the father's vacancy, garnered him a nomination at the 16th Seoul International Youth Film Festival for the Best Young Actor Award.

He portrayed Park Gun, an underdog high school student struggling to survive among the strong in a realistic and comical way.

[26] He also starred in a KBS2 Drama Special Avici, playing the role of a model student from an elite high school, but lacks the ability to empathize with others' pain, who tried his best to cover up his mom's murder.

[27] In 2016, he gained more recognition after co-starring in the hit KBS2 historical series Love in the Moonlight as a skilled swordsman known as Kim Byung-yeon.

[32][33][34] In July 2017, Kwak was cast as Michael, the main protagonist in the Korean adaptation of The Elephant Song play, which ran from 6 September to 26 November at the former Suhyeonjae Theater in Seoul.

[37][38] On 27 November 2017, Kwak carried the Olympics flame for the 2018 Pyeongchang Games in Gokseong, South Jeolla province as part of the torch relay.

[41][42][43] He also starred in JTBC's romantic comedy series Gangnam Beauty,[44] which was a hit and gained renewed recognition for Kwak.

[49] In 2019, Kwak made a special appearance in SBS drama Doctor Detective, portraying Jung Ha-rang, a screen door service engineer from a vocational high school, who was destroyed by an industrial accident.

[68] In 2022, Kwak appeared in the movie 6/45 as an observer in the South Korean front force[69] and in the MBC drama Big Mouth as a convicted scammer called Jerry.

On 26 February 2014, not long after Kwak finished his Inspiring Generation drama promotion, his mother died of an illness.