[2] He saw a runway video from a fashion show starring Lee Soo-hyuk on the internet in his third year at Ulsan High School [ko] amidst his deliberation of possible future career prospects for college.

[1][3] With his growth in enjoyment for magazines and pictorials, he soon wanted to become a model;[4] however, due to familial expectations, he prepared for the college entrance exam during the second semester of high school.

[2] To pursue his dream, Jang went to Seoul after passing the college entrance exam and enrolled in the musical acting department at Yong In University.

His performance to "Doom Dada" by T.O.P of Big Bang garnered attention due to its fast-paced tempo and flow while its execution was praised despite his occupation as a model.

[14] Jang cited the drama as a turning point in his acting career as he received various offers to appear in commercials and television shows and felt its effects when he was approached or recognized by people in their 40s and 50s.

[7][15] With Yang Se-jong and Woo Do-hwan, Jang was dubbed a part of "Most Popular Actors Born in 1992" and "Rising Super Rookies" by media outlets in South Korea.

[22] Jang made his big screen debut in the crime action film Bad Guys, based on the OCN drama of the same name, which premiered in September 2019.

[24] In 2021, Jang starred in the Netflix original romantic comedy film Sweet & Sour alongside Chae Soo-bin and Krystal Jung.

Jang's last project before his mandatory enlistment was the SBS television series Now, We Are Breaking Up with Song Hye-kyo, Choi Hee-seo and Kim Joo-hun, all of which was pre-filmed before his departure in August ahead of its airing in November.

[30] Having transitioned from modelling to acting himself, Jang stated: "I want to be faithful to my main job, movies and dramas, and be able to stand on the runway like Cha Seung-won during the fashion show seasons.

[32] Jang also briefly cited South Korean veteran actor, Ha Jung-woo as a role model following his appearance on SBS' Healing Camp.

[36] Since then, he became advertising models for brands including Guess Korea, TBJ, Jill By Jillstuart, Philips, and Nepa (clothing) [ko].

[37][38] In March 2019, Natuur, an ice cream franchise under Lotteria chose Jang as a model for their products, a first after 7 years following their rebranding.

A representative revealed through the selection process, they believed his image who constantly challenges himself with diverse roles while also pursuing an active lifestyle fits well with the innovative concept they wish to portray.