After a supporting turn in the hit series The Greatest Love (2011), he returned to the big screen in the well-received indie Poongsan (2011).

Along with Danny Ahn, Son Ho-young, Kim Sun-a and producer and singer-songwriter Park Jin-young, the group was initially called "GOT6".

He has since clarified in his 2012 cooking show Yoon Kye-sang's One Table that he left the group with the intention of leaving the entertainment industry altogether as he had begun to detest the spotlight, but stumbled upon an opportunity to try acting and enjoyed it.

[12] He enlisted in the Republic of Korea Army on December 7, 2004, and was assigned to the 102nd Reserves at Chuncheon, Gangwon Province, on the Korean Demilitarized Zone.

[15] As late as June 2011, his military service still earned him public attention, when a round-cheeked photo of him in uniform "went viral" among South Korean internet users.

[19] Later that year, he took a dual role in the comedy television series Who Are You?, playing a cold-hearted corporate raider who, in the aftermath of a traffic accident, becomes possessed by the spirit of a cheerful deliveryman for a few hours each day.

After doing a lighter role in the slice-of-life drama Triple,[22] Yoon starred in the movie The Executioner, which examined capital punishment in South Korea; it debuted at the 14th Busan International Film Festival.

[31] Calling it "a meaningful project," Yoon enjoyed the difficult acting challenge of telling the story only through his eyes, facial expressions and body movements.

After starring in the third season of popular sitcom High Kick!,[35] he was cast in the action thriller The Suspect,[36] but withdrew when co-star Choi Min-sik backed out.

[49][50] Yoon wrote the lyrics for the song "Wind" (바람), which was released after the conclusion of their nationwide tour as a gesture of gratitude to fans.

[51] In 2014, Yoon starred in the melodrama series The Full Sun, in which he played a con man who enters a complicated romance with a jewelry heiress.

[57] He next starred in Last, a cable series based on Kang Hyung-kyu's webtoon about a fund manager whose financial ruin leads to life among the homeless living underground at Seoul Station,[58] followed by Love Guide for Dumpees (titled A Dramatic Night in Korean), a play-turned-movie about a man and woman who agree to be casual lovers but end up finding something more.

[61] Yoon then played a disabled man in the film The Bacchus Lady, a bittersweet drama about an elderly prostitute helmed by E J-yong.

Entertainer and 2AM member Jo Kwon became president of the franchise while Yoon and his friends remain the owners and still run the original café.

[72] In an interview with GQ Korea in April 2021, Yoon revealed that he had suffered a brain aneurysm and underwent urgent endovascular coiling surgery the year before in 2020.