Who co-founded Twitter and served as its first CEO?

Jack Dorsey co-founded Twitter and served as its first CEO. He developed the original idea for a short-message service while working at Odeo, and he helped build the first Twitter prototype with Noah Glass. Dorsey sent Twitter’s first message on March 21, 2006, and became the company’s inaugural chief executive.

Dorsey served as CEO from 2006 until 2008, when Evan Williams took over the role. Dorsey later returned as Twitter’s CEO in 2015 and remained in that position until 2021. He also co-founded the payments company Square, later renamed Block, and led that company while holding other roles.

The other listed names are closely connected to Twitter’s creation. Noah Glass helped develop the early service and played an important role in its naming. Biz Stone and Evan Williams were also co-founders and major early executives. Evan Williams eventually became CEO after Dorsey’s first tenure, which can cause confusion, but Jack Dorsey is the canonical answer to the question asking for Twitter’s first CEO.