[11] In 1994 he joined musical Subway Line 1 [ko], where he met Sul Kyung-gu, Hwang Jung-min, and Jang Hyun-sung.

Produced by PMC Production under co-CEOs Song Seung-hwan and Lee Kwang-ho, Nanta premiered in Korea at Hoam Art Hall in October 1997.

[12][13][14] After participating in the Edinburgh Festival Fringe in 1999, Nanta toured over 20 countries around the world, including Europe, Japan, Southeast Asia, Australia, and North America, and has recorded an audience occupancy rate of over 90% to date.

Originally scheduled for the first half of 2004, the Broadway run was rescheduled due to the success of its Los Angeles performance.

One day, Kim received a drunken call from his former understudy, Yoon Jeong-hwan, who was yelling at him, "Why are you rolling gimbap?

In April, Kim returned to the stage in the black comedy play Jjamppong, which Yoon Jeong-hwan had written and directed.

[17][18] In the 2007 encore performance from April 5 to June 10, 2007, at Shotick Theater 2, Kim played the role of Shin Jak-ro, the head of the Chunraewon Chinese restaurant family.

[8] Feeling left behind by his former colleagues after a hiatus, Kim focused on his theater works, approaching acting with a "rookie" mindset.

[6][13] In November, Kim made his television debut with a minor role as Mr. Jin in the KBS drama Beautiful Days [ko].

[19][20][21][22] Kim Won-hae then joined the cast of the third encore performance of The Story of the Neulgeun Thief, which includes existing members such as Park Cheol-min, Hyeong Hyeong-gwan, Park Gil-soo, Jeong Kyung-ho, and Min Seong-wook, as well as Seo Hyeon-cheol, Lee Jun-hyuk, Lee Sang-hong, and Choi Deok-moon.

[23][24] His performance in the play The Story of the Neulgeun Thief earned him the 1st Young Drama Award, with a prize of 3 million won.

[25] In 2009, Kim reprised the role of Shin Jak-ro in a black comedy play called Jjamppong.

It explored the disintegration of family in Korean society through black comedy, with the actors alternating in the role of Lee Bong-jo, the authoritarian and violent father.

Kim said, "I tried really hard to learn the art of comedy acting from my senior, but it's really something you're born with, and I can't catch up."

Jang Jin selected Kim as one of the 16 members of tvN's "Saturday Night Live Korea" in 2011, where he began to gain popularity.

In this work, he portrayed the character Kimura Takuya, who was armed with a complex about his appearance and a clumsy charisma, and he quickly rose to the top of the comedy scene in Daehak-ro.

Written and directed by Jang Jin, the play tells the story of actor Jin-woo, who takes on various roles to make ends meet.

Set in a theater dressing room during a production of Hamlet, the play captures candid moments of actors preparing for the final performance.

In the drama "Misaeng: Incomplete Life" (2014), he received acclaim for his role as the new head of the Sales Team, portraying a realistic and strict boss.

He received critical acclaim for his roles in Strong Woman Do Bong Soon and While You Were Sleeping, winning awards for his performances.

In the drama, he played Manager Chu of the accounting department and was shown making fried rice with knife skills that were almost acrobatic.