Rick Nealis, shown here doing race prep in 1998, has seen the Marine Corps Marathon grow during his tenure. (Tracy A. Woodward/The Washington Post)

In a framed photo displayed prominently in his office, Rick Nealis is in the background, looking off to the side. A mischievous grin appears across his face as he stands behind talk-show host Oprah Winfrey.

It’s almost as if he knows he has pulled off one of the biggest heists in marathon history.

As the second-year race director of the Marine Corps Marathon in 1994, Nealis convinced Winfrey to run in Washington instead of in the Chicago Marathon, her local race. Winfrey’s participation on that cold and rainy fall morning, her first and only marathon, is partially credited with inspiring casual runners to add a marathon to their bucket lists.

Now in his 25th year in charge of the race dubbed “The People’s Marathon,” Nealis has seen the race evolve from a niche community of mostly competitive runners to one that draws tens of thousands participants annually, including this Sunday. The sport has changed, and Nealis, 63, has witnessed and assisted its growth from his perch as race director of one of the largest road races in the country.

“When I was running, it was always about speed,” Nealis said this month in his office at Marine Corps Base Quantico. “But now it’s about coming across the line and feeling good. . . . Some people feel the sport has suffered for that, but I think, if it wasn’t for that, we’d be this small track and field event that no one really understood.”

Nealis first served as race director while on active duty for the Marine Corps in 1993, then was the first civilian to hold that position when he retired from the military in 1995.

He remembers each year through the lens of the Marine Corps Marathon and vividly recalls the public relations and logistics issues of each race. In his first year, there was controversy around the men’s champion, who admitted to cutting corners. The following year — the “Oprah year” — gave Nealis clout and fame in the running community, but there was also drama stemming from runners urinating in Arlington National Cemetery.

In 2001, Nealis wasn’t sure he’d be able to receive all of the permits needed to hold the race after the Sept. 11 terrorist attacks, and in 2002, the D.C. sniper shootings had his team on high alert throughout the first three weeks of October.

To Nealis, one of the biggest changes over the years has been the amount of security dedicated to the race. When he began, the law enforcement bill was zero, Nealis said, but now “security, safety and risk assessment is on the forefront.”

“He’s had a lot of obstacles thrown at him,” said Al Richmond, a 78-year-old Arlington resident who has run every Marine Corps Marathon since its inaugural race in 1976. “I don’t know how they do it, frankly. Just thinking about getting the number of people out on the course to support it, all the young Marines and bands — logistically, it has to be a nightmare and an unbelievable process to prepare for.”

While the race has grown and the demographics have changed — the ratio of men to women is far more balanced now than when Nealis began — one thing has remained the same: There is no prize money.

Because of that, the race typically doesn’t draw an elite field of the world’s best marathoners, and Nealis admitted it gnaws at him that the men’s course record, Jeff Scuffins’s time of 2 hours 14 minutes 1 second, was set 30 years ago.

But he said he realizes that’s what makes the race special. It’s not about elite runners dropping in for a cash prize; it’s about the military and the everyday runners who make up the sport.

“It’s so rewarding to see everyone coming in happy, getting their medal and smiling,” said Julian Smith, the longtime race director of the Cooper River Bridge Run 10K in Charleston, S.C., and a friend of Nealis’s. “There’s just so much excitement and happiness.”

Winfrey had run Smith’s race that April, before her marathon debut, and Smith provided Nealis with Winfrey’s contact information. Nealis said he believes his race’s emphasis on the casual runner was another reason he was able to entice Winfrey to come.

Over the years, Nealis, a Philadelphia native, has left his mark on the race in both subtle and visible ways. One of his first decisions as race director was to order green race shirts as a nod to the Philadelphia Eagles. In 2007, he started presenting a stuffed penguin to the final official finisher of the race in memory of Megan McClung, a Marine Corps officer killed in Iraq.

Nealis’s next mission is to get more kids from all socioeconomic backgrounds involved in the sport. Starting next year, the race will offer anyone under 17 a discounted entry fee.

“My swan song is to leave the sport healthy,” he said, “and not on the downslide.”