• Birth name: Yoon Doo Joon (Hangul: 윤두준)
• Date of birth: July 4, 1989 (1989-07-04) (age 21)
• Position: Leader, Vocalist, Rapper

Doo Joon is the leader of BEAST.He was a trainee from JYP Entertainment. He was featured in the Mnet documentary Yeolhyeolnama (Korean: 열혈남아, Hot Blooded Men) with 2AM and 2PM but was eliminated. He was then transferred to JYP Entertainment's sister company, Cube Entertainment. Before his debut with BEAST, he auditioned for High Kick Through the Roof and was offered a role in the sitcom but turned it down to focus on his music career. He became a member of reality-variety series Danbi, a segment part of MBC's Sunday Sunday Night line-up.
Doo Joon was featured in AJ's music video for "Nunmureul Dakko" (Korean: "눈물을 닦고", "Wipe the Tears") as a rapper along with Jun Hyung before they debuted as part of BEAST. He was also a rapper for Gavy NJ's song "Sun Flower".
Doo Joon worked with Shin Saekyung on an ad for premium jeans brand, Buckaroo
As Girls' Generation member Taeyeon will be leaving MBC Radio FM4U 91.9Mhz ‘Chin Chin Radio’ , he was chosen as the temporary DJs for two weeks together with solo singer IU. Doo Joon was featured for Gina’s album title song ‘I’ll Back Off So You Can Live Better’ music video. 

Hyun Seung

• Birth name: Jang Hyun Seung (Hangul: 장현승)
• Date of birth: September 3, 1989 (1989-09-03) (age 20)
• Position: Lead Vocalist, Lead Dancer

Hyun Seung first received media attention as a trainee under YG Entertainment with nickname So-1, when he was preparing to debut as a member of Big Bang. He appeared in 10 out of 11 episodes of the Big Bang Documentary, but wasn't chosen to be a part of the final group formation by YG's president. He received a lot of concerns from Cube's management when BEAST was being formed, as the first thing the members were instructed to do was to have Hyun Seung gain weight.

Jun Hyung

• Birth name: Yong Jun Hyung (Hangul: 용준형)l
• Date of birth: December 19, 1989 (1989-12-19) (age 20)
• Position: Main Rapper

Before debuting as a member of BEAST, Jun Hyung was first a member of XING, known by his stage name as Poppin' Dragon. He is noted to have unusual hairstyles.Jun Hyung was also featured in fellow member's AJ's music video "눈물을 닦고" ("Wiping the Tears") as a rapper with Doo Joon. Along with fellow BEAST member Yo Seob, MC and comedian Lee Hyukjae, Moon Hee Jun (formerly of H.O.T.) and Kim Sook, they welcomed Japanese tourists for "Visit Seoul 2010" campaign, where Korean celebrities and Japanese tourists explore Seoul in MBC's Star Guide Doshiraku to raise awareness of Seoul's famous areas as well as its delicious cuisine.
Jun Hyung was the featured rapper in Hyuna's solo debut single "Change". Jun Hyung along with 4minute were also featured in "Heard 'Em All" for Amerie's Asian version of the album In Love & War. He was also a guest rapper for K.Wills song "Present".  He also starred in MBC High Kick Through the Roof for a scene. He was featured in the rap making and featuring for 4minute’s album "Hit Your Heart" where his composing skills are dutifully noted. Jun Hyung was featured for Gina’s album title song ‘I’ll Back Off So You Can Live Better’ music video and his appearance will be giving the opposite vibe from Doo Joon.

Yo Seob

• Birth name: Yang Yo Seob (Hangul: 양요섭)
• Date of birth: January 5, 1990 (1990-01-05) (age 20)
• Position: Main Vocalist

Yo Seob is the main vocalist of BEAST. Noted to be the "cute" member of BEAST, his various hairstyles have received much attention, being compared to that of a Fairy Pitta and a Shih Tzu among other things. Yo Seob was a former JYP Entertainment trainee. He moved agencies, to M Boat Entertainment (a former sister company of YG Entertainment) then to Cube Entertainment. He was also known for his self-created videos and parodies. He was a backup dancer for AJ's music video "눈물을 닦고" ("Wiping the Tears") and "Dancing Shoes".
Along with fellow BEAST member Jun Hyung, MC Lee Hyukjae, Moon Hee Jun (formerly of H.O.T.) and Kim Sook, Yo Seob welcomed Japanese tourists for "Visit Seoul 2010" campaign, where Korean celebrities and Japanese tourists explored Seoul in MBC's Star Guide Doshiraku to raise awareness of Seoul's famous areas as well as its delicious cuisine.On July 16th, 2010, Yo Seob participated in the More Charming by the Day official soundtrack in promotion for the film with the song "Happy Birthday".

Gi Kwang

Main article: AJ (singer)

• Birth name: Lee Gi Kwang (Hangul: 이기광)^[
• Date of birth: March 30, 1990 (1990-03-30) (age 20)
• Position: Vocalist, Main Dancer

Gi Kwang was initially a trainee under JYP Entertainment.He later transferred to sister entertainment company, Cube Entertainment where he originally debuted as a solo singer by the stagename, "AJ". Cube Entertainment then decided to have him join BEAST where he redebuted under his given name. He is known as SaeHo in MBC High Kick Through the Roof, and was selected as MC for MBC's Sunday Sunday Night segment Hot Brothers.
Gi Kwang is featured in K.Will's music video for the song, Present.He was also chosen as the model for the ‘Ice Tea Tio’ from DongSuh Foods.

Dong Woon

• Birth name: Son Dong Woon (Hangul: 손동운)
• Date of birth: June 6, 1991 (1991-06-06) (age 19)
• Position: Vocalist, Rapper

Dong Woon was a trainee from JYP Entertainment and was the last member to join BEAST and is also the maknae (youngest) of the group.