Yong-Sin Lee is a South Korean voice actress and singer recognized for her extensive work in dubbing anime series and video games into Korean. She was born in Seoul, South Korea, on February 27, 1975. Lee began her career in the entertainment industry after winning a voice talent contest, which leveraged her skills in singing and vocal performance. Prior to becoming a voice actress, she worked as a commercial jingle singer and a television shopping host. She formally entered the voice acting industry in 2003 by joining the voice acting division of On-Media, which later became part of CJ ENM.

Her breakthrough role came in 2004 with the Korean dub of the anime Full Moon, where she voiced the main character Mitsuki Koyama, known as Luna in the Korean version. The role was significant as the character was an aspiring singer, requiring Lee to perform six songs within the story, which showcased her vocal abilities and helped establish her reputation in the industry. Following this success, she became a prominent voice for many leading female characters in anime dubs targeted at Korean audiences.

Lee's filmography is extensive and includes a wide variety of notable roles. She is the Korean voice of Rika Furude in the When They Cry - Higurashi series, Nanoha Takamachi in Magical Girl Lyrical Nanoha, and Eiko Aizawa in Squid Girl and its second season. She also voiced Jiyu Nonohana in Jubei-Chan 2: The Counterattack of Siberia Yagyu and Noeru Sugawara in Gunparade Orchestra. In the comedy series Sexy Commando Gaiden: Sugoi yo!! Masaru-san, she took on the roles of Doctor Mariko and Meso. Other major credits include Sakura in Tsubasa: Reservoir Chronicle, Temari and Kurenai Yuuhi in Naruto and Naruto Shippūden, Soifon in Bleach, Akeno Himejima in High School DxD, and Haru Miura in Reborn!. Her work extends to video games as well, where she is known for voicing Ahri in League of Legends and the female version of Noble 6 in Halo: Reach.

In addition to voice acting, Lee has pursued a career as a singer, leveraging her musical talent which was evident from her early work. In 2010, she held her first solo live concert, a milestone for a voice actor in South Korea. She achieved another significant milestone in 2013 by releasing her debut studio album, Type Control, which was reported as the first full-length album recorded by a voice actor in the country. She continues to release music, with a single titled Don't blame yourself released in December 2023. Lee has expressed that her diverse life experiences, including part-time jobs and travel, have been invaluable in her work, allowing her to quickly understand and portray a wide range of characters.