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Jack Dorsey

Jack Dorsey is an American technology entrepreneur and software developer best known as a co-founder of Twitter, now known as X, and Block, formerly Square.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 27, 2026|2 min read| Fact-checked

Jack Dorsey is an American technology entrepreneur and software developer best known as a co-founder of Twitter, now known as X, and Block, formerly Square. He was born in St. Louis, Missouri, on November 19, 1976. His companies and platforms are widely used in Canada, affecting Canadian users, businesses, and creators.

Early life and education

Dorsey was born in St. Louis, Missouri, in 1976. Public biographies describe him as an American entrepreneur and developer who became interested in web and communication software early in his career.

Twitter/X

Dorsey co-founded Twitter in 2006, helping create one of the world’s best-known social media platforms. He later served as CEO in two separate periods before leaving the role in 2021.

Square/Block

After Twitter, Dorsey helped build Square, a mobile payments company that expanded into a broader financial technology business and rebranded as Block in 2021.

Later projects

Dorsey has continued to support decentralized communication and internet infrastructure projects, including Bluesky and Bitchat. These efforts reflect his long-running interest in communication systems outside traditional centralized platforms.

Key facts

  • Co-founded Twitter in 2006 with Evan Williams and Christopher Stone.
  • Helped establish Square, a digital payments company later renamed Block in 2021.
  • Served multiple terms as Twitter’s chief executive before stepping down in 2021.
  • In 2025, he unveiled Bitchat, a decentralized messaging app using Bluetooth mesh networking.
  • His work spans social media, digital payments, and decentralized communication tools.
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Canadian context

Dorsey’s companies and platforms are widely used in Canada, including social media services and digital payment tools that affect Canadian users, businesses, and creators.

Frequently asked questions

Who is Jack Dorsey?
Jack Dorsey is an American technology entrepreneur best known for co-founding Twitter/X and Block, formerly Square.
When was Jack Dorsey born?
He was born on November 19, 1976, in St. Louis, Missouri.
What companies did Jack Dorsey co-found?
He co-founded Twitter and Square, which later became Block. Sources also associate him with Bluesky.
Did Jack Dorsey leave Twitter?
Yes. He stepped down as Twitter’s CEO in 2021 after serving in that role during two separate periods.
What is Bitchat?
Bitchat is a decentralized messaging application unveiled by Dorsey in 2025 that uses Bluetooth mesh networking rather than the internet.
Why is Jack Dorsey notable?
He is notable for shaping major platforms in social media and digital payments and for promoting decentralized communication technologies.

References

  1. Britannica — https://www.britannica.com/money/Jack-Dorsey
    Supports: Birth date; birthplace; co-founding Twitter; role in Square/Block; Bitchat mention
  2. Wikipedia — https://en.wikipedia.org/wiki/Jack_Dorsey
    Supports: Full name; co-founding Twitter, Block, and Bluesky
  3. Biography.com — https://www.biography.com/business-leaders/jack-dorsey
    Supports: Birth date; birthplace; founding Twitter and Square; career overview
  4. Business Insider — https://www.businessinsider.com/jack-dorsey-twitter-creator-billionaire
    Supports: Twitter leadership timeline; Square/Block rebrand; resignation as Twitter CEO
  5. All American Speakers — https://www.allamericanspeakers.com/celebritytalentbios/Jack+Dorsey/384063
    Supports: Bluesky association; Bitcoin-related advocacy; Bitchat mention