Keith Gill: From star runner to investment disruptor – With insights from The Wall Street Journal

As it turns out, in the earliest footage of him on YouTube, he also needs a drink. In a 2009 video with only a few hundred views as of Friday, Gill runs four laps in his Stonehill College singlet for a small crowd of bored college kids on hand to witness his first mile run in six months, following an injury. They cheer him on as he pants through a 4:33 mile, losing a bet to break 4:30—and then immediately collapses on the track.

"Get this man a beer," one friend says.

Gill liked to run the four miles from his Brockton home to his future college nearby. He still holds the Stonehill records in the 1000-meter (2:24.73) and the mile (4:03.43). He was a college All-American in track and cross country, a Division-II national indoor men's track athlete of the year and a Stonehill sports Hall of Famer as "one of the most decorated runners in the rich history" of the school.

But his transformation into a regionally successful distance running star was about as likely as his blindsiding of Wall Street.

Gill got his first taste of competition when he showed up as a skinny 13-year-old to one of the kids races that Dave Gorman has organized in a local park for the past 40 years. He immediately blew away the competition. Gorman, who didn't know that Gill was Roaring Kitty until a reporter told him on Friday, couldn't fathom what he had just witnessed.

"Jeez, Keith, that was unbelievable," he remembered telling him. "Are you going to run in high school?"

He had never really thought about it. Gill always planned to play baseball instead. But in the same way that stocks became an obsession when he could no longer run, running became his life once he failed to make the baseball team.

A decade before he would become famous on the Reddit forum WallStreetBets, he was known to runners for his posts on a defunct popular running message board called DyeStat.

"Who the heck is keith gill?" one LetsRun.com user posted in 2007.

"He is a God on Dyestat," another responded. "Funny as hell and fast as hell. I'll be cheering for him the rest of his career."

Steve Underwood, a former DyeStat editor and moderator of its message boards, still remembers Gill as "Wizard," one of the ringleaders in a rowdy forum known as The Playground. Gill was already forging a reputation online as someone worth following.

"He was mischievous, and I'm pretty sure I banned him a few times, but he was clever," Underwood said. "He wasn't just some dumb kid posting obscene, vulgar stuff. You could tell there was intelligence behind what he was doing."

Gill was a good high-school runner who got better in college, but he was also trapped in a boom-and-bust cycle as he battled injuries. A nagging iliotibial band issue in high school became excruciating pain in college—both physically and mentally. "When running becomes your life and you can't do it any longer, it's like everything is taken away from you," he told the Boston Herald in 2006. "It kills."

Only after consulting with several doctors over many months was he diagnosed with mononucleosis and anemia. Gill was prescribed a multivitamin that would send his performance the way of GameStop's stock price.

"Once we put him on iron pills," coach Karen Boen told the Boston Globe in 2007, "he took off."

In early 2008 he lowered his indoor mile personal best in successive weeks and blazed to a school record 4:03.43. It was the fastest time in Division II that season, but it wasn't fast enough to win the race. A miler from an Ivy League school nipped him with a 4:02.76. There was an important lesson that day: Even when you think you're peaking, your performance can always get better.

Or it can get worse—fast.

A case of what Gill called Achilles tendinosis brought his running hopes crashing down. His last race was in March 2008, right around the time that Bear Stearns collapsed, and he graduated in 2009 straight into the financial crisis.

But it was always Gill's mindset that separated him from every other runner Boen encountered in nearly a quarter-century at Stonehill. "Keith had the ability to go into a place mentally and with such intense focus that I had never experienced in other athletes," she said on Friday. His legs failed him. His mindset didn't.

The same focus that Gill brought to the pursuit of New England track and field glory led him into the exploration of unloved stocks. He became a Chartered Financial Analyst, committed himself to stock picking, and saved the passion that he once poured into running for the audience on the YouTube channel he started last summer as he worked a marketing job for Massachusetts Mutual Life Insurance Co.

The bet that would become his own personal four-minute mile began when he turned bullish on GameStop and bought his first shares in June 2019. Its price was about $5. It closed on Friday afternoon at $325.

His latest "GME YOLO update" on Reddit shows a profit of more than 4,000%.

Fidalgo, of Brockton High, and Gill's former distance coach Joe LeMar hadn't missed the news. While texting on Friday morning, they wondered about the ways in which Gill might remember his track days now that he was fabulously wealthy. Fidalgo guessed he might even build them an indoor track. Just hours later, in a Wall Street Journal article, Gill announced that was one of his goals. To those who knew him, it was never in doubt.

"I know Keith," LeMar texted Fidalgo. "Brockton and Stonehill are going to be all set."

There is just one person who won't be able to participate: still hobbled by injuries, Gill says he no longer runs.

Write to Joshua Robinson at Joshua.Robinson@wsj.com, Ben Cohen at ben.cohen@wsj.com, Julia-Ambra Verlaine at julia.verlaine@wsj.com and Gunjan Banerji at gunjan.banerji@wsj.com