Jack Patrick Dorsey, born on November 19, 1976, in St. Louis, Missouri, is an American entrepreneur and technology pioneer best known for co-founding Twitter (now X) in 2006 alongside Noah Glass, Biz Stone, and Evan Williams. He served as Twitter's CEO from 2007 to 2008 and again from 2015 to 2021, during which time the platform grew into a global social media giant influencing politics, culture, and public discourse. Dorsey's vision for Twitter emphasized brevity and real-time communication, but his tenure was marked by controversies including accusations of censorship, content moderation biases, and regulatory scrutiny over misinformation and user privacy. In 2021, he stepped down as CEO, handing the role to Parag Agrawal, and later sold his stake following Elon Musk's acquisition of the company in 2022.

Alongside Twitter, Dorsey co-founded Square (rebranded as Block, Inc. in 2021) in 2009, revolutionizing mobile payments and fintech accessibility for small businesses. As Block's co-founder, chairman, and former CEO, he expanded the company into cryptocurrency services through subsidiaries like Cash App and TBD, reflecting his strong advocacy for Bitcoin and decentralized finance. Dorsey also founded Bluesky in 2019 as a decentralized social media protocol, positioning it as an alternative to Twitter amid growing concerns over centralized control. His entrepreneurial pursuits extend to investments in health tech, renewable energy, and philanthropy via the Start Small initiative, which donated over $1 billion to COVID-19 relief and racial justice causes in 2020.

Dorsey's influence spans technology, finance, and activism, with a personal philosophy shaped by interests in meditation, fasting, and Bitcoin maximalism. He has faced criticism for his dual CEO roles at Twitter and Square, leading to shareholder pushback, and for Twitter's handling of political content, including the 2020 U.S. election and deplatforming of figures like Donald Trump. Despite these challenges, Dorsey remains a prominent voice in tech, residing primarily in Miami, Florida, after relocating from San Francisco.