The 39th Annual Capital Pride Parade moves along 17th Street. For the first time the U.S. Armed Forces color guards participated in the parade. (Astrid Riecken/For The Washington Post )

Bill Morgan, 76, was kicked out of the Citadel, the military college in South Carolina, because he was gay. He lied so he could serve in the Air Force, in the closet, wary and silent, as gay friends were drummed out. So when the eight-man U.S. military color guard marched for the first time at the head of Capital Pride, the District’s gay pride parade, Morgan was, for a moment, speechless.

“Never in a million years,” Morgan said, a string of rainbow beads circling his neck. “I never imagined that I could come from there to here. I’m just glad I lived long enough to see it.”

Afeefah Asare, 30, of Northern Virginia, who just moments before the color guard passed had been whooping it up and yelling “Happy Pride!,” stopped in shock and stared at the passing flags of the Army, Navy, Air Force and Marines.

“That is awesome,” she said solemnly. “It means everybody’s in now.”

The military color guard was another first in the 39-year history of the parade. Leaders of OutServe, an organization of gay military service men and women — who have been able to serve openly since 2011 — say this is the first time an armed services color guard has led a pride parade in the country.

Last year, several mainstream religious groups marched for the first time. Organizers say that with attendance growing — organizers expected upward of 100,000 spectators — the once flamboyantly fringe affair has gone mainstream.

This year, while there were the usual rainbow-colored banners, colorful beads and the occasional underwear-clad youth dressed like Playboy bunnies, the route was also lined with strollers, dogs and a whole lot of ordinary looking people.

“I’m here to show my kids that there’s noting wrong with being gay or lesbian,” said Adriana Gonzalez, 25, watching the parade with her 1-year-old in an orange stroller and her 5-year-old holding her hand. “I want them to know that no matter where you come from, or who you are, we’re all the same.”

The theme this year, “Build Our Bright Future,” includes party events such as the Thunderdome, for a “hot night of leather and gear,” but also seminars on financial planning for retirement hosted by AARP.

“It’s like any other fun D.C. event anymore,” said a clean-cut man in a green T-shirt who gave his name only as John. “It’s pretty mainstream.”

The parade, like many others across the country that sprang up after the 1969 Stonewall riots, began 39 years ago as a flamboyant and at times shockingly sexual in-your-face protest against the homophobia, discrimination and police raids like those at the Stonewall Inn in New York that kept gay, lesbian, bisexual and transgender Americans in the closet and on the margins of society.

This year, the parade is being sponsored by Marriott, a nod, its Mormon owners say, to the estimated $200 billion LGBT travel market. On five of its hotels in town, the company has hung enormous “#LoveTravels” banners that feature well-known gay and transgender Americans, including professional basketball player Jason Collins, who came out last year, and transgender fashion model Geena Rocero.

Amtrak, another corporate partner, has an LGBT blog extolling the virtues of arriving at gay pride events by train “rested, relaxed and ready for the celebration and fun of pride.” Other corporate sponsors include Metro, several hotel chains, banks, stores such as Walgreens and companies including Bud Light, Food Lion and Absolut Vodka.

“While hotel occupancy numbers for this weekend will not be available until next week, we know LGBT travelers who come to D.C. for pride and year round, for business and leisure, make a big impact on the local economy,” said Kate Gibbs, of Destination DC, formerly the DC Convention & Tourism Corporation.

“In January, the Advocate named D.C. ‘the gayest city in America.’ This endorsement, combined with an ever- ­increasing community of LGBT-friendly and owned businesses, and Destination DC’s dedicated ads, we’re eager to capitalize on the spending power of LGBT travelers whether they are coming for a family vacation or a party-filled pride weekend.”

Justin Zielke, 34, who lives nearby and never misses a pride parade if he can help it, said this year’s parade, with the color guard and corporate sponsorships, felt exciting.

“Finally, the military and big business understand that diversity is important, not just racial diversity, but LGBT issues, a new area of human rights,” he said. “I’m excited to see this here. But you know, we don’t really need it as much as they do in smaller cities and town, like Birmingham, Alabama, and other places” where gay rights have yet to take hold.

The mainstreaming of the gay pride parade reflects the growing acceptance of gay and lesbian Americans.

“In the earlier years, it was more of a protest and there was more of a political nature to the event because we had not been recognized,” said Bernie Delia, chairman and president of the Capital Pride Alliance, organizer of the parade. “We don’t have as much to protest here. This year, it’s not much of a protest, but a celebration. The world has changed a lot.”

Since last year’s groundbreaking Supreme Court decision striking down same-sex marriage bans, same-sex couples can legally marry in 19 states and the District of Columbia, and the 31 states that have laws or constitutional amendments restricting marriage to one man and one woman are being challenged in court, according to Human Rights Campaign, a gay rights group.

A majority of the largest employers now provide benefits to same-sex partners and spouses of employees, the group reports, and nine states and the District of Columbia allow unpaid leave under the Family Medical Leave Act for domestic partners or same-sex spouses. A recent Washington Post poll found that 50 percent of Americans surveyed said same-sex couples should have a constitutional right to marry. Among respondents under 30, the share rose to 77 percent.

In the District, David A. Catania (I-At Large) has served as the City Council’s first openly gay member since 1997. He and D.C. Mayor Vincent C. Gray (D) stood by as Wilson High School principal Pete Cahall said he was tired of hiding and came out as gay this week on the school’s second annual Gay Pride Day. Cahall said he was emboldened, in part, by Michael Sam, the first openly gay athlete to be drafted by an NFL team, whose celebratory kiss with his boyfriend upon hearing the news was broadcast widely earlier this year.

Parade organizer Delia sounded a somber note, however, saying that while the growing acceptance of the LGBT community into the American mainstream was a cause for celebration, gays and lesbians in other countries are still persecuted. In Russia, President Vladi­mir Putin signed a law that makes illegal to promote same sex relationships to minors — a ban that has been interpreted as outlawing gay pride parades and raised fears that the children in such unions could be taken away.

“So we march to celebrate, to remember the way things were, and in solidarity with our brothers and sisters who aren’t able to march, who aren’t able to come out publicly,” Delia said. “We march for people who don’t enjoy all the hard-won freedoms we have here.”