John Gentry, the chief executive officer of supply-side platform OpenX and a pioneering figure in adtech, died on Wednesday evening after a prolonged battle with cancer. He was 58.
In a poignant LinkedIn post scheduled to appear after his passing, Gentry reflected on his life with characteristic grace and gratitude. “If you are reading this, it means that I’m no longer around and lost my fight with cancer,” he wrote. “While I am dying earlier than most, I outlived myself by 28 years, thanks to a kidney transplant and modern medicine, and I’ve had a wonderful life. I am a lucky and thankful man.” He went on to celebrate the relationships he cherished, noting that “the best part of the ride has been all the amazing relationships I’ve formed over the years,” and even injected humor by urging readers to tell his children, Jack and Grace, “to work harder.”
OpenX confirmed Gentry’s death in a statement to Adweek, echoing the sentiments shared by colleagues who remembered him as more than a leader—a mentor, advocate, and friend. Matt Sattel, president of OpenX, captured this in his tribute: “JG’s belief in me changed my life. He was more than a leader to me. He was an advocate, a mentor, and a friend. JG believed that doing the right thing and building a strong business could go hand in hand, and showed us that it was possible to lead with both strength and humanity, even when it was hard.” Sattel highlighted Gentry’s ability to push teams to “think bigger, act with clarity, and put our people first,” lessons that would endure long after his departure.
Gentry’s career spanned decades of transformation in advertising and media, marked by innovation and resilience. A graduate of Northwestern University’s Kellogg School of Management and UCLA, he began in the 1990s at the Walt Disney Company, directing distribution strategy for ABC cable networks. He later held senior roles at Overture, an early digital advertising leader acquired by Yahoo for $1.63 billion in 2003, where he served as senior vice president and general manager; as chief revenue officer at financial services firm Green Dot; and as president of adtech startup Spot Runner. Joining OpenX as an advisor in 2012, he rose to president and was appointed CEO in 2020, guiding the company through seismic shifts including the rise of header bidding in the mid-2010s, evolving privacy regulations, and an antitrust lawsuit against Google.
Under Gentry’s stewardship, OpenX solidified its reputation as an independent, people-first adtech player. He contributed significantly to header bidding innovations and supply-side identity technology, helping publishers monetize inventory more effectively in a fragmented digital ecosystem. Michael Todd, a former OpenX chief technology officer and now an executive at Silver Lake Partners, credited Gentry with building the company’s culture: “John was instrumental in building OpenX into the independent, people-first ad tech company it became known for over the past decade. He combined deep industry intuition with genuine care for those around him, and he pushed everyone to operate at a higher standard.”
Tributes poured in across social media and industry channels, painting a portrait of a man whose influence extended far beyond boardrooms. Jason Fairchild, cofounder and CEO of TV adtech firm tvScientific, who worked with Gentry at GoTo.com and later recruited him to OpenX, called him “an industry leader, a pioneer, a collaborator… my best friend, mentor, and biggest fan.” Fairchild described Gentry as “a force of nature” grounded in empathy: “The force was uncompromising and often pushed people out of their comfort zones, but it was grounded in empathy and care for the person.” Wayne Blodwell, who leads the programmatic practice at Stagwell agency Assembly Global and consulted for OpenX, recalled Gentry’s selflessness: “JG was a thoughtful man that helped me out on numerous occasions without asking for anything in return. His openness and kindness will be missed by those around him and the wider industry.”
OpenX’s official statement reinforced this legacy: “JG meant so much to so many of us at OpenX, and our thoughts and deepest sympathies are with his family and friends during this difficult time. JG believed that even in a demanding industry, it was possible to lead with both rigor and humanity. We will carry that forward.” In an era of adtech defined by cutthroat competition and rapid disruption, Gentry stood out for his decency, accessibility, and commitment to collective success, never treating colleagues as mere stepping stones.
Gentry’s final years at the helm were especially remarkable. Diagnosed with cancer, he led OpenX for six years while undergoing treatment, attending board meetings, navigating strategic pivots, and inquiring about employees’ families on every call. This unyielding dedication, even as his health declined, exemplified the humanity he championed. As one observer noted, Gentry hailed from adtech’s builder era, when debates centered on structure and trust rather than dominance—a mindset he embodied until the end.
The outpouring of grief on platforms like LinkedIn, typically reserved for polished professionalism, revealed the depth of Gentry’s impact. Hundreds shared raw remembrances, breaking through the industry’s veneer of detachment. For out-of-home advertising professionals and the broader media ecosystem, Gentry’s passing serves as a reminder of the individuals who shape markets not just through technology, but through relationships and integrity. His trailblazing contributions to programmatic evolution will persist in OpenX’s platform, but it is his personal legacy—leading with strength, empathy, and an unwavering focus on people—that resonates most profoundly.