Yook Sung-jae (Hangul/Hanja/Romanization: 육성재/陸星材/Yuk Seong-jae; born May 2nd 1995 in Yongin City, Gyeonggi Province), simply known as Sungjae, is a South Korean singer, actor and television personality. A member of the boy band BtoB, he has also starred in dramas Plus Nine Boys (2014), Who Are You: School 2015 (2015) and The Village: Achiara's Secret (2015). He is a member of Okcheon Yook Clan (옥천 육씨/沃川陸氏), a clan which is originated from Okcheon County, Northern Chungcheong Province - same as the First Lady Yook Young-soo, mother of the current president of Korean Republic, Park Geun-hye and wife of the former president Park Chung-hee.
Sungjae debuted as a member of BTOB. The group officially debuted on March 22, 2012. Sungjae along with Ilhoon and Lee Minhyuk took part in writing lyrics for their debut song “비밀(Insane)”. On July 2014, Sungjae became a presenter for the program, A Song For You with Kangin of Super Junior and Amber of f(x). Later that year, Yook Sungjae was casted in variety series, Hitmaker as member of Hyundon and Defconn's parody project boy group, Big Byung. He was given the stage name of YookDuk and was also joined by Got7's Jackson, VIXX's N and Hyuk. The group released a music video for their single entitled Stress Come On on August 19, 2014. He was also casted in the television drama Plus Nine Boys as a 19-year old Judo athlete named Kang Min-gu. In late 2014, he became a cast in reality variety show Real Men and left in 2015.
On January 2015, Big Byung made their comeback with "Ojingeo Doenjang" together with the Season 2 of Hitmaker. Sungjae received his biggest break when portrayed a leading role in the teen drama, Who Are You: School 2015 as Gong Tae-kwang who is an idiotic but problematic child of the Sekang High School's director. He acted alongside Kim So-hyun and Nam Joo-hyuk. He also received a good feedback when he competed in a mystery music show, King of Mask Singer. He joined as Tired Bumblebee and reached the third stage of the competition with the song "Thanks" by Kim Dong-ryul. Currently, he is still in a virtual marriage in season 4 of the reality show We Got Married with Red Velvet's Joy. He starred in the horror-mystery drama The Village: Achiara's Secret as the male lead Park Woo-jae. His role is identified as police officer Park Woojae.
It was also revealed that after the television series, Who Are You: School 2015 ended, Yook Sungjae was able to land in a total of 4 solo endorsements including mobile app Cash Slide, clothing brand Black Yak with Jo In-sung, Hazzy's Accessories with his co-star in Who Are You: School 2015, Kim So-hyun, and lastly a shopping website named G-Market.
By the year-end, Yook received multiple awards in KBS Drama Awards, SBS Drama Awards, and MBC Entertainment Awards. He received the Best Couple Award with Kim So-hyun for the teen drama Who Are You: School 2015 and New Star Award for the mystery drama The Village: Achiara's Secret. He also won Best Couple Award with Red Velvet's Joy, and the Best Male Rookie (in Variety) for their appearance in the variety show, We Got Married.