CEO at DoubleVerify
Leading DoubleVerify's NYSE IPO and championing transparency, brand safety, and fraud prevention as foundational pillars of a trustworthy digital advertising ecosystem.
Last updated Feb 27, 2026 by AI Enrichment
Mark Zagorski is one of the most influential operators in digital advertising technology, best known for leading DoubleVerify through its successful IPO on the New York Stock Exchange in April 2021 and cementing the company's position as the gold standard for digital media measurement, brand safety, and ad fraud prevention. Under his leadership, DoubleVerify has expanded its product suite to include attention measurement and performance analytics, making it an indispensable partner for the world's largest advertisers and media platforms. His tenure has been defined by a relentless push for accountability and transparency in a digital advertising ecosystem historically plagued by opacity. Before joining DoubleVerify in 2020, Zagorski served as CEO of Telaria (now Magnite) and prior to that held the CEO role at Undertone, a high-impact digital advertising company. His career spans more than two decades in AdTech and media technology, giving him a rare combination of operational depth and strategic breadth across both the buy and sell sides of the industry. He has consistently demonstrated an ability to scale software and data businesses, navigate complex market transitions, and build enterprise-grade solutions trusted by Fortune 500 brands. Zagorski is a frequent speaker at major industry conferences and a vocal advocate for raising industry standards around measurement integrity, attention metrics, and the responsible use of data. He has helped shape the conversation around post-cookie identity solutions and the future of digital media quality, positioning DoubleVerify as a proactive standards-setter rather than a reactive compliance tool.
Telaria (now Magnite) (2018-2020)
Undertone (2012-2017)
Nielsen (2010-2012)