He is the co-founder of Twitch, a popular video game streaming platform Amazon acquired in 2014. Mr Shear will take over as CEO from Mira Murati, who was publicly aligned with Mr Altman.
Mr Shear stepped down as the CEO of Twitch in February this year and was named a part-time advisor to Y Combinator, a San Francisco-based startup, said Washington Post.
Born in 1983, Emmett Shear completed graduation from Yale University in 2005 with a Bachelor's degree in Computer Science.
For 16 years, he worked on live video for the internet starting with Justin.tv, which later became Twitch. Mr Shear lives with his family in San Francisco.
Y Combinator is the same company that Mr Altman himself was head of from 2014 to 2019. He returned to OpenAI's office on Monday morning saying it would be the "first and last time" he wore a guest badge.