Tristan O’Tierney, who helped develop Square’s original payment app, has passed away

Tristan O’Tierney, a co-founder of the payments company Square, has passed away at age 35. According to the San Francisco Chronicle, O’Tierney died last weekend in Florida of addiction-related causes after a hospital was unable to revive him.

In the Chron’s piece, it reports that Square co-founders Jack Dorsey and Jim McKelvey hired O’Tierney to develop Square’s original mobile payment app in early 2009, and that O’Tierney is generally credited as a co-founder.

He left the company in 2013, eight years after coming to the Bay Area, where he also worked as a software engineer at Yahoo for nearly two years and worked briefly at Apple, VMware and Tapulous.

In recent years, O’Tierney had been working as a freelance photographer in Los Angeles, according to his LinkedIn profile. (You can check out some of his work here.)

He was also the director of Mobile at a short-lived San Francisco-based company, Voteraide, that aimed to empower voters by enabling them to interact with candidates and elected officials as verified voters.

O’Tierney was reportedly in Florida as part of a months-long rehabilitation program.

Dom Sagolla, a former colleague and roommate of O’Tierney, tells the Chron it was he who introduced O’Tierney to Dorsey 11 years ago. He says O’Tierney had helped to develop the official iPhone app for Barack Obama’s 2008 presidential campaign and that O’Tierney and Dorsey met at an iPhone-app development event that he organized. “I will really miss him and want his memory and legacy to last,” said Sagolla.

O’Tierney clearly had varied interests. Though he studied computer science at the Rochester Institute of Technology, he also later obtained a Master of Fine Arts degree from the San Francisco Art Institute. On Instagram, his descriptor reads: “Square co-founder turned traveling photographer. Searching for the meaning of life and got lost along the way.”

Pictured above: a landscape photo of Death Valley by O’Tierney.