Gender: Male Age: 34 Birth: July 20, 1992, Jecheon-si, Chungcheongbuk-do Height: 162.3 cm Weight: 88.8 kg Features: The eldest member of Bomulsum and the founding member who first proposed forming the group. Although he is a year older than the others, the members call him 'dangsin' (you) or 'Mr. Lee Hyunseok' and rarely call him 'hyung'. In fact, they are so close that he is more often called 'ya' or 'neo' (hey/you). He was quite slim during the early days of their YouTube career in 2016–2017. Because of this, the members tease him by saying the original member was replaced by the current one. He is currently said to be suffering from hair loss. He runs a YouTube channel with his wife, Lee Jia.

Gender: Male Age: 33 Birth: May 21, 1993, Gangseo-gu, Seoul Weight: 74 kg Height: 178 cm Features: A massive gaming addict who often hears, "Donghyun, you shouldn't play games so much." According to the members, he often skips company dinners or meetings to play Overwatch. He is said to be bad at eating spicy food. He loves cheese immensely. Consequently, one of his nicknames is 'Chee-Donghyun,' and cheese-related scenes appear in their videos whenever people start to forget. When eating pizza, he loves cheese so much that he adds extra cheese to a cheese pizza and even sprinkles Parmesan cheese powder on top. While not tone-deaf, his singing ability is lower than the other members. It's not that he's a terrible singer, but because Kang Minseok and Lee Hyunseok are so good, he seems worse by comparison. He likes the color blue. He has a habit of shaking his legs when anxious and hitting his knees when nervous. He is the only left-handed member of Bomulsum. He is the only member from Seoul and the metropolitan area. He is part of the 1st graduating class of Seoul School of Performing Arts (SOPA); he revealed that he saw the recruitment poster for the 1st class on the school bulletin board and took the entrance exam as an MC, bringing cue cards for the first time. He is the same age as Kang Minseok.

Gender: Male Age: 33 Birth: August 14, 1993, Haenam-gun, Jeollanam-do Weight: 71 kg Height: 178.9 cm Features: Known for having severe facial asymmetry. While most people have some degree of asymmetry, his is pronounced enough that people sometimes ask if he has a medical condition. His jaw is tilted, and the right side of his face looks slightly sunken. Because of this, his crooked face is often used as a comedic subject. He has the best anger management skills in Bomulsum. Compared to Kim Donghyun or Lee Hyunseok, he swears or loses his temper far less often. He is the exact opposite of Kim Donghyun, who has a strong stomach but often explodes emotionally. He is the only member of Bomulsum who does not have a fear of heights. He is a huge figure/statue otaku and is often 'punished' by having his collectibles damaged. Many evaluate him as handsome. He is considered to have top-tier visuals not just within the Bomulsum channel but among comedy YouTubers in general. Since he is a comedian, his looks are often downplayed, but he is tall and has warm features. To be precise, rather than being conventionally handsome, he has a very unique look, but since his fellow YouTubers often have very distinct personalities in their appearance, he tends to be rated highly by comparison. He is the same age as Kim Donghyun.

The subscriber nickname is 'Pirates.' They are affiliated with Sandbox Network. Their signature greeting is 'Aryeong-haseyo~ Heoit!' This is the collective description for the group.