Oscar Oiwa was born in 1965 in São Paulo. After receiving a B.A. in archtecture and urbanism at São Paulo University in 1989, he moved to Tokyo, Japan. While living and working there, his art was featured in numerous exhibitions. His home and studio have been in New York City since 2002. He became an American Citizen in 2010.

Among his awards are an artist residency at The Delfina Studio Trust, London, in 1995, a Pollock-Krasner Foundation grant in 1996, a John Simon Guggenheim Memorial Foundation grant in 2002, and an Asian Cultural Council Fellowship in 2002.
His works has been shown widely throughout the United States, South America, Asia, and Europe. In 2008 he had a solo exhibition at Museum of Contemporary Art Tokyo. The exhibition traveled to Fukushima Prefecture Museum of Art and Takamatsu City Museum of Art. In 2011 he had a solo exhibition at National Museum of Fine Arts, Rio de Janeiro.

His works are in the permanent collections of The National Museum of Modern Art Tokyo, Museum of Contemporary Art Tokyo, Hiroshima City Museum of Contemporary Art, Toyota Municipal Museum of Art, Arizona State University Art Museum, Phoenix Museum of Art, among others.