Business leaders and politicians jammed into a tent in the Seaport on Monday to celebrate the coming of a 1,000-plus-room Omni hotel. But they chose not to focus on one important aspect of the project’s history.

It almost didn’t happen.

Governor Charlie Baker put the hotel’s future in doubt two years ago when he shelved an expansion of the Boston Convention & Exhibition Center across the street, citing the costs. Massport, the hotel site’s owner, eventually pursued a much smaller facility, soliciting proposals with as few as 250 rooms.

In the end, Massport officials got the massive project that they wanted. Omni Hotels & Resorts won the bidding with plans to open a $550 million project, the Seaport’s biggest hotel, in early 2021. Construction on the 800,000-square-foot complex, which will feature two towers, is expected to begin next year.

Monday’s event was in part aimed at highlighting Omni’s role. (Omni also owns the much smaller Parker House in Boston.) Robert Rowling, chairman of Omni parent TRT Holdings, said he was impressed that Baker, who also spoke at the event, had reached out personally to encourage Omni to complete the South Boston deal.

“We want to help fill that convention center,” Rowling said. “It’s going to be something that you all are proud of.”

Texas-based Omni is unusual in that it develops, owns, and operates its hotels, giving it more flexibility with financing.

Omni’s local development team includes Davis Cos. and the Taylor Smith Group, hotelier Robin Brown, and a number of minority investors. Massport encouraged the participation of minority- and woman-owned businesses in the bidding.

The company figured out how to build a big hotel on one Massport site, instead of on two, reducing the land costs. This was done by incorporating a chunk of smaller-than-normal rooms into the design.

Massport’s staff picked the Omni project as the top choice for the 2.1-acre site at the corner of D and Summer streets by last fall, and the agency’s board voted to approve the Omni proposal last month.

Massport officials say the agency will receive about $100 million from the long-term lease. Massport agreed to a reduced rate in the early years, but officials say they’re still getting the market value when all payments are totaled.

Meanwhile, the convention center expansion remains an open question. It’s hard to imagine that happening without a subsidy, likely from hotel taxes. But the politicians who represent South Boston aren’t giving up on that one: US Representative Stephen Lynch and state Senator Linda Dorcena Forry both renewed the call for the expansion during their remarks. The new hotel might drive that project now, rather than the other way around.