Yūji Ueda is a veteran Japanese voice actor born on June 15, 1967, in Fukuoka Prefecture. He is a graduate of the Literature Department's Theater Studies program at Tamagawa University. Initially active under his birth name in kanji, he changed his stage name to the hiragana version,うえだゆうじ, on July 1, 2004. Throughout his career, he has been affiliated with several agencies, including ARTSVISION and Ohata Production, and is currently represented by PomaRancz.

Ueda made his voice acting debut in 1992. A significant breakthrough came in 1996 when he landed the popular role of the brawler Sanosuke Sagara in Rurouni Kenshin. That same year, he secured his first leading roles as天河明人 in Martian Successor Nadesico and as the titular character Hamel in Violinist of Hameln. In 1997, he began his long-running association with the Pokémon franchise, taking over the role of Takeshi (Brock), a part he would play for many years across numerous TV series, specials, and theatrical films. His extensive work in the franchise also includes voicing numerous Pokémon, most notably Musashi's Sonansu (Jessie's Wobbuffet).

Ueda is widely recognized for his extraordinarily wide vocal range and versatility. He is capable of portraying a vast array of character types, from hot-blooded heroes and handsome young men to comedic fools,冷酷无情 villains, and even eccentric individuals. This adaptability has led industry professionals like director Hiroshi Nagahama and sound director Kazuya Tanaka to describe him as an all-around voice actor. His comedic timing is notable in roles such as the over-the-top Shin Morita in Honey and Clover and the death metal musician Johannes Krauser II in Detroit Metal City, for which he performed the character's intense songs. He also demonstrated his range in the absurdist comedy Gyagu Manga Biyori.

Beyond his many roles in the user's list, Ueda's career is marked by several other iconic performances. He voiced the lazy tennis prodigy Akutagawa Jiro in The Prince of Tennis and the mysterious Sokushinbutsu in X. In the mecha genre, he played Billy Katagiri in Mobile Suit Gundam 00. His work in video games is also prominent, with notable roles including早乙女好雄 in Tokimeki Memorial,泽村将马 in the Rival Schools series, and several characters in the Samurai Warriors series, such as Keiji Maeda and Kojiro Sasaki.

Ueda comes from a musical family and is a trained violinist, a skill he has incorporated into his voice acting work, such as performing on character song CDs. He is also known for his love of cooking, his left-handedness, and his habit of reading psychology and philosophy books to better understand the characters he plays. Following the 2011 Tōhoku earthquake and tsunami, he engaged in charity activities alongside fellow voice actor Masaya Onosaka.