He was a fan in an owner’s clothes. Not just a backer of a ballclub but a believer in the best of us.

Padres owner Peter Seidler did not accept as fact the notion that his team could not rise above its market size, take over its town. Nor did he accept as fate the concept of the richest nation in the world leaving its most vulnerable citizens in the streets.

News of Seidler’s passing on Tuesday at age 63 from an undisclosed cause was sad because the Friars and their fans lost a man who invested so much of his worth and his self into the roster and the Petco Park experience. And it was sad because this was a conscientious citizen who wanted to make San Diego, as he put it, “world class” in both the standings and in its ability to take care of its own.

A two-time survivor of non-Hodgkin’s lymphoma, Seidler was a fighter who tried as hard to address the city’s homelessness problem as he did to construct a World Series-caliber roster.

“I've banned, in my conversations anyway, calling [homelessness] a complex or overwhelming problem," he told the San Diego Union-Tribune in 2017. "It's a big problem, but the scientists at research institutions trying to break the genomic code, that's a complex problem. This just has a lot of components to it. It takes diligence and focus and execution."

Seidler was born into a rich baseball bloodline. He was the grandson of Brooklyn and Los Angeles Dodgers owner Walter O’Malley and the nephew of O’Malley’s son and successor, Peter.

But the club that Seidler, who was co-founder of the private-equity investment firm Seidler Equity Partners, helped purchase in 2012 had nowhere near the vibrant past of that Dodgers franchise. On the contrary, the Padres had, at that point, rarely been relevant. They had only reached the playoffs five times dating back to 1969, had never won a World Series, had rarely posted strong attendance figures and, in a related development, had never spent aggressively.

Determined to end the drought for a city without a major sports championship, Seidler changed the conversation about his club. He became the largest stakeholder in the team after the 2020 season. This was just three years after the Chargers bolted for Los Angeles after 56 years in San Diego, leaving a void in the hearts of local sports fans that Seidler aimed to fill.

By the time he took full control of the club, the franchise-record free-agent signing of Manny Machado had ushered in an especially earnest era of Padres baseball, and Seidler amplified it over the past few years by authorizing another big signing of Xander Bogaerts, trades for the likes of Juan Soto, Yu Darvish and Blake Snell, and a mammoth extension for Fernando Tatis Jr. The Padres reached the National League Championship Series in 2022 and entered this year with the third-highest payroll in the sport -- a rank that at one time was unfathomable for the Friars.

Through no fault of his own, Seidler’s 2023 Padres were a disappointment on the field. But the same could not be said at the gate, where they drew a franchise-record 3.27 million fans to Petco. It was the second-highest attendance in MLB – again, a rank that had once been inconceivable in San Diego.

It can feel a mountainous task to punch above your weight in the Major Leagues, but that’s nothing compared to overcoming the impact a pandemic, economic forces, addiction and mental health issues and rising housing costs can have on the country’s already shameful homelessness issue. Seidler did not shy away from either undertaking.

Seven years ago, Seidler formed the “Tuesday Group,” which hosted weekly meetings to address homelessness issues throughout San Diego. The foundation has provided bridge shelters with as many as 300 beds in the downtown area, has provided work experience, job training, meals and water to homeless people and has incentivized constructive behavior with a Community Care Kit program that provides backpacks filled with protective clothing, hygiene necessities and other needed goods. In 2019, the group successfully lobbied then-Mayor Kevin Faulconer to use the Golden Hall arena as a homeless shelter.

Seidler’s passion proved contagious. The Padres say donations for the Padres Foundation, which supports underserved communities in the region, grew nearly 10-fold during Seidler’s time as chairman of the team. Under his leadership, the Padres also strengthened relationships with the Rady Children’s Hospital, Monarch School, Make-A-Wish Foundation, Build A Miracle and Veterans Village of San Diego, and the “Pedal the Cause” fundraiser for local cancer research raised more than $18 million.

That the Padres remained unable to win the big one under Seidler is nothing more than a footnote to his story and his legacy. To have energized a fan base, helped the homeless and added a rich chapter to an impressive baseball family lineage is legacy enough. Peter Seidler gave the best of himself and inspired others to do the same. May he rest in peace.