In 2013, he starred in the lead role in the weekend drama, Passionate Love. In 2014, he also starred in the web drama 6 Persons Room, where Sung played a construction safety engineer who suffers an injury and finds himself in a hospital surrounded by strange patients. He also starred in 2015 in the web drama Noble, My Love, and featured in KBS’s romantic comedy series Oh My Venus playing a professional MMA fighter. He is also a musical Disc jockey, and conducts DJ activities under the name Roiii. Additionally, he has performed in various nations including China, Hong Kong, Thailand, Malaysia, Singapore, and Indonesia.
In 2018, his first action film Brothers in Heaven was released in January. Sung acted alongside Jo Han-sun as fraternal twins. Sung was also cast in the sitcom, The Sound of Your Heart: Reboot, and the romantic comedy web drama I Picked Up a Celebrity on the Street. In 2019, Sung came back to small screen with the romantic comedy-drama Level Up playing a character of a company restructuring expert.
By end of 2020, he came back to web drama with My Secret Star playing a character of a Hallyu star who is hiding a big secret and meets an entertainment journalist who risked her life to get on the scoop, played by Vietnamese actress Hoàng Yến Chibi. In 2021, he starred as a lawyer who has trouble in maintaining his marriage in seasons 1 & 2 drama Love (ft. Marriage and Divorce). Sung also played the role of Raphael in the SBS romantic comedy drama Woori the Virgin based on American series Jane the Virgin, reuniting with New Tales of Gisaeng co-star Im Soo-hyang in 2022.
