Retired Sen. John Breaux’s nearly 20-year reign as ceremonial head of the annual Washington Mardi Gras extravaganza will come to an end Saturday night when the Louisiana Democrat — decked in festive green, purple and gold robes and crowned with a feathered headpiece — will lead his final procession of masked revelers into the ballroom of the Hilton Washington.

Breaux, who left Congress earlier this year after more than three decades in the House and Senate, must vacate the post of captain of the Mystick Krewe of Louisianians — the nonprofit organization that sponsors the festivities — because its rules stipulate that the captain must be a sitting member of the Louisiana delegation. Breaux was allowed to stay on this year because Louisiana had several hotly contested House and Senate seats in last November’s elections.

“Like everything else, you want to serve your term,” said an upbeat Breaux, who recently joined the lobbying firm Patton Boggs and two New York financial firms. “I wanted to do it one more time because we didn’t know what the delegation was going to look like.”

The celebration has been a staple of the Washington social scene since its founding more than a half-century ago as a modest gathering of homesick Louisianans.

Officially, only 2,500 tickets are sold to the three-day event’s culmination, a ball, but it regularly attracts upwards of 3,000 — mainly Louisianans — and is rivaled only by the Texas State Society’s “Black Tie and Boots Inaugural Ball” in scale. The presence of Members of Congress and other high-ranking Louisianans at the festivities has led lobbyists and corporations to mount a profusion of unofficial parties and gatherings during the week of the celebration.

“People do a lot of business over the weekend,” said Rep. William Jefferson (D-La.).

While Breaux sidestepped the question of how he will commemorate his farewell — “One time I came in in a coffin, but this year I’m not sure what I’m going to do,” he said — he did divulge, with a laugh, that he was prepping for his final go-round by trying on his costume and boots and “practicing [his] drinking.”

Longtime attendees of the celebration said Breaux’s departure marked the end of an era.

“It will have a huge effect on Mardi Gras,” said former Rep. Jimmy Hayes, who represented a Louisiana district first as a Democrat and later as a Republican. Hayes, now a lobbyist with Adams & Reese, a Louisiana-based law and lobbying firm, dubbed Breaux “the linchpin” of the event.

“With all due respect to our delegation,” Hayes said, “I don’t think any of them in the House or Senate have remotely the interest that John did.”

Breaux assumed his Mardi Gras role from iconic Sen. Russell Long (D-La.), who held the Mystick Krewe of Louisianans captainship beginning with the organization’s founding in the late 1950s, said krewe senior lieutenant Joe Broussard, whose father was pivotal in organizing the event in the 1940s. Except for a brief stint by Long’s cousin, Gillis Long, in the early 1980s, Long held the title until he passed it to Breaux.

Among Breaux’s most vivid memories of his tenure was the time his then-aide Norma Jane Sabiston — now chief of staff to Sen. Mary Landrieu (D-La.) — got her formal gown stuck in the hotel’s escalator, trapping her in a squatting position for an hour and a half as throngs of attendees looked on. He also recalls the image of Russell Long “sitting on the floor of the Washington Hilton putting on a leotard.”

In addition to Breaux’s unparalleled “esprit de corps,” krewe officials and longtime attendees said the former Senator deserves credit for overseeing the growth of the event during his watch. He also helped found an economic development luncheon held in conjunction with the event to bring together representatives of local Louisiana chambers of commerce, business and civic leaders and Members of Congress from the Bayou State. Earlier, local chambers had held individual events, Sabiston said.

Over the years, Breaux’s association with the event has taken on legendary proportions. His old costume — not the one he will wear this year — will be donated to the Mardi Gras museum in New Orleans. “They’re very expensive,” he joked of his costumes. “It’s almost the same price as Donald Trump’s wedding dress.”

Breaux’s impending departure as krewe captain isn’t the only change coming to the event. Over the past year, the composition of the Louisiana delegation has been dramatically altered, with the retirement of 13-term Rep. Billy Tauzin (R), the defeat of Rep. Chris John (D) in a Senate bid, the elevation of Rep. David Vitter (R) to the Senate, and the party switch of Rep. Rodney Alexander from Democrat to Republican in August. For the first time in the event’s history, the delegation now boasts a Republican majority.

But none of the changes is expected to dampen the bipartisan spirit of the event.

“There are hard feelings, but we leave those at the door,” chuckled John.

And organizers said that though Members may come and go, the event would proceed as usual in the future.

“The delegation is the delegation,” said Ted Jones, a krewe senior lieutenant and Baton Rouge lobbyist. “We enjoy having them, but if someone leaves” that doesn’t change things, he said.

In addition to hosting hospitality suites in the Hilton during the week of the event, Louisiana Members also head their own marching krewes, made up of supporters and friends of the individual Member. Among the krewes are “Jindal’s Jesters,” “Boustany’s Bogus Lords and Ladies” and “Mary’s Minstrels” — in honor of GOP Reps. Bobby Jindal and Charles Boustany and Landrieu.

The festivities, which kick off tonight with the “Louisiana Alive” party, continue on Friday with a dinner-dance before concluding Saturday night with a formal Mardi Gras ball replete with a parade and royal court.

This year’s theme — “Louisiana-Abundant Links” — as well as the king and queen are chosen by the event’s chairman, Jefferson. Jefferson, who became chairman in an annual rotation among delegation members, picked his daughter Nailah Anan Jefferson as queen.

The scene inside the ballroom on this final night has been described as bordering on other-worldly by several past attendees.

“Where but the Mardi Gras can you meet the ‘Shrimp and Petroleum’ festival queen, the train of her gown richly embroidered with the image [of a] shrimp climbing an oil derrick?” asked Heritage Foundation senior legal scholar James Swanson in an e-mail.

Over the years, high-profile attendees have included everyone from automaker Henry Ford to President Gerald Ford. The first program for the ball was narrated by legendary CBS News anchor Walter Cronkite, Broussard said.

As to Breaux’s replacement, krewe elders — the five senior lieutenants who elect the captain and make up the executive committee — said the decision is still months away. Breaux himself was mum on whether he had a preference for his successor.

“We have to talk to the delegation and feel them out,” said Broussard.

But there already appears to be at least one contender for the position.

Landrieu, whose election in 1996 prompted the formal integration of women into the krewe, has made no secret that she’s eyeing the post.

“Senator Landrieu is very interested in being captain of the krewe,” said Sabiston, adding that Landrieu was open to “taking turns with her colleagues.” (According to new krewe rules, Breaux’s long run at the helm will not be repeated: Successors will be limited to a maximum of four years.)

But whoever that lucky Member turns out to be, Breaux — who will become captain emeritus after this weekend — says it will likely take some time for the individual to grow into his or her new role.

“It’s a learning process,” he advised his yet-unknown successor. “It takes a while not to worry about making a fool of yourself.”