Jack Dorsey has built — and stepped away from — two of the most impactful companies of the modern internet.

He co-founded Block Inc. (originally Square) with Jim McKelvey in 2009, took it public in 2015, and later rebranded it in 2021 as the company expanded beyond payments into a broader financial ecosystem.

Before that, he helped launch Twitter in 2006 alongside Evan Williams, Biz Stone, and Noah Glass. Dorsey served twice as CEO, shaping the platform during its most critical years, before ultimately stepping down from the board in 2022.

Across payments and social media, his work has influenced how people transact, communicate, and build businesses online.

With an estimated net worth of $5.8 billion, Dorsey’s career isn’t just about building companies — it’s about defining entire categories of the internet.