He portrayed Jin-Soo Kwon in Lost, Chin Ho Kelly in Hawaii Five-0, Gavin Park in Angel, and Ben Daimio in Hellboy.

He also provided the voice of Chief Benja in the animated film Raya and the Last Dragon (2021) and Johnny Gat in the Saints Row video game series.

Since the role required him to speak exclusively in Korean, he said he was forced to quickly relearn the language, which he had not spoken with any great frequency since high school.

Throughout the show's run, he, along with his fellow cast members, received numerous accolades, including a 2006 Screen Actors Guild Award for Best Ensemble.

[9] Kim provided the voice of the character Johnny Gat for the Saints Row video game series, which debuted in 2006.

[14] In February 2010, shortly after Lost's conclusion, it was announced that Kim would join the CBS reboot Hawaii Five-0 as Chin Ho Kelly, the role originally made famous by actor Kam Fong.

He departed the show together with Grace Park, the female lead, in late June 2017 prior to the eighth season due to a salary dispute with CBS.

He is an executive producer on The Good Doctor and joined the show during its second season in the role of chief of surgery, Dr. Jackson Han.

[24] Kim provides the voice of Chief Benja in the Disney animated film Raya and the Last Dragon, which was released in March 2021.

[27] After testing positive for COVID-19, he spoke out against the xenophobia and racism related to the COVID-19 pandemic, stating: "Please, please stop the prejudice and senseless violence against Asian people.

"[28] Prior to the 2022 runoff election in Georgia, Kim tweeted about state laws that make it challenging for students at Historically Black Colleges and Universities (HBCUs) to establish their eligibility to vote, citing VoteRiders as a resource for more information about valid voter ID.