He is best known for his leading roles in the popular television series School 2017 (2017), The Tale of Nokdu (2019), Search (2020), Daily Dose of Sunshine (2023), Like Flowers in Sand (2023–2024), and My Man is Cupid (2023–2024).

It was reported that he had come across a robber with a lethal weapon threatening a convenience store clerk in Seoul's Gwanak District, and that he devised a quick plan to have the culprit arrested.

[15] In 2019, Jang starred in the historical romantic comedy drama titled The Tale of Nokdu along with actress Kim So-hyun.

[22] In 2021, Joseon Exorcist, a show where Jang Dong-yoon was one of the leading stars, was cancelled after airing two episodes during the controversy over historical inaccuracies, such as incorrect use of Chinese traditional props.

[23] Later in October 2021, it was announced that the animated film Tae-il featuring Jang's voice will be released in December 2021.

[33] On August 30, 2022, Jang donated 6 million won in scholarship money to his father's retirement ceremony.