Remembering Oath’s Jay Seideman: ‘He Was The Type Of Guy Many Of Us Strive To Be’

Jay Seideman was a father, husband, athlete, musician and mentor. A guy who many said was hysterically funny, cooler than the other side of the pillow and could get others to rally behind his cause.

Seideman, Oath’s SVP of advertiser demand platforms who drowned Dec. 7 while surfing at San Francisco’s Ocean Beach, left a powerful legacy among the many friends who knew him both professionally and personally.

Seideman was 43 and is survived by his wife SaraJane and two sons, Auggie and Sebastian.

“We got to grow up in our industry together, from the early days running around the digital media business in San Francisco, to getting married and having families,” said Brendan Moorcroft, co-founder of the consultancy Unbound. “We all got to experience it all together. Jay always made it feel like we were all part of one big family!”

Many recalled Seideman’s sense of humor.

“He could be hysterically funny, but he was always smart, always on point and always kind,” said Jed Nahum, head of ad buying systems at Pandora. “I enjoyed his ability to mix efficacy with humor and silliness. Often I found myself wondering how I could be more like Jay. I already miss him terribly.”

Professionally, Seideman was a skilled dealmaker, combining his vast knowledge of advertising with an easy personality to get things done.


“Jay was one of the kindest and [most] honest people to grace this planet,” said Jivox CRO Moritz Loew, who was mentored by Seideman.

Barry Dougan, VP of display advertising at Microsoft, recalled Seideman’s tenure there from 2010 to 2015.

“Personally, Jay was the type of guy many of us strive to be,” Dougan said.

He had a rare combination of confidence, intelligence and dry wit, said Sean Finnegan, partner of Chameleon Collective.

And Seideman was a trailblazer – and a key contributor to the development of Microsoft’s programmatic display business, said Kya Sainsbury-Carter, VP of global partner service in Microsoft Advertising.

She remembered how he helped build the business by developing trusting relationships with strategic advertisers. Seideman’s leadership was inspirational, an alchemy of being collaborative and goal-driven.

“He was truly the loveliest person to work with and someone who raised the bar for our industry every day that he touched it,” Sainsbury-Carter said.

Eric Dahlberg, who supervised Seideman at Microsoft, added: “He handled every situation with just the right mix of professionalism, intellect and humor!"

A large part of Seideman’s friendships came from his willingness to take risks. Moorcroft, who worked with Seideman over the past 18 years, remembered how they would experiment together, unconstrained by conventional wisdom.

“What I personally loved more than anything was we got to create and try things together that no one else was trying at the time,” Moorcroft said. “It led to close friendships across the industry. His is a relationship I value and cherish, which makes this time so difficult.”

Tim Mahlman, Oath’s president of advertising and publisher strategy, recalled Seideman’s eternal optimism.

“His belief in doing what's right made him unafraid to say what he felt,” Mahlman said in a statement to the Oath team. “He always knew how to motivate me, and he knew how to pick me up when things were not going well. Jay was always a glass half-full kind of guy. He lived by the belief that anything is possible if you want it badly enough. Even on bad days he somehow knew how to find the strength to show a smile, and he always put others first.”

Jay brought joy and passion to everything he did both professionally and personally, said ZergNet COO Brian White. “I always really admired him for that,” he said.

Added Mahlman: “I am so lucky to have been his teammate and even luckier to call him my friend. Thank you, Jay. You will be missed, brother.”

Seideman’s colleagues at Oath set up a Gofundme page to help support his family.

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