One ran as a moderate dealmaker, willing to work across the aisle to get things done. The other ran as a political newcomer who would bring his experience in the worlds of business and finance to bear on the country’s fiscal problems.

Both won expensive, closely watched races in November, and now the real work begins.

The Washington area’s two newest members of Congress — Sen. Timothy M. Kaine (D-Va.) and Rep. John Delaney (D-Md.) — were sworn into office Thursday, arriving on Capitol Hill at a crucial political moment that will test the platforms they used so effectively on the campaign trail.

Having just passed a small-scale deal to avert the worst effects of the “fiscal cliff,” Congress in the coming months will face new fights over raising the nation’s debt ceiling and averting steep automatic cuts to defense and domestic spending, known as the “sequester.”

Amid the swirl of official ceremonies and receptions, trailed by family and well-wishers, both men said they were eager to get down to business.

“While we’ve had some fun this afternoon . . . my real excitement is starting to do the work,” Kaine said. “I just feel like there’s so much work to be done.”

Kaine said he believed he and Sen. Mark R. Warner (D-Va.), a fellow centrist former governor, “have a way of doing things that has something to offer at the national level, especially on these issues that will occupy a lot of our attention in the next 60 days.”

The upcoming fiscal negotiations would seem to cry out for the kind of bridge-builder Kaine says he will be in the Senate. Yet many of the chamber’s moderates, including Warner, have been relegated to the sidelines in recent months as the top leaders from both parties went to the bargaining table with the White House.

“I wish we had more people running on such bipartisan credentials, but the fact is the centrist dealmakers are somewhat irrelevant in the Senate these days given how hyperpartisan it is,” said Jim Manley, a former aide to Senate Majority Leader Harry M. Reid (D-Nev.).

Republicans spent much of the 2012 campaign questioning whether Kaine was such a moderate, pointing to his service as Democratic National Committee chairman and close relationship with President Obama.

With defense cuts looming, Kaine will have a voice in the debate as a member of the Armed Services Committee, a plum for Virginia and its huge military presence. The freshman was also named to the Foreign Relations Committee, replacing retired Sen. James Webb (D-Va.) on both panels.

And Kaine will get a slot on the Senate Budget Committee, putting to use the ledger-balancing experience he earned as Virginia governor.

During his campaign, Kaine frequently accused opponent George Allen and other Republicans of playing politics with the debt ceiling. Kaine reiterated Thursday that he agreed with President Obama that raising the debt ceiling should not be conditioned on any other demands by Republicans.

But Kaine also said he thought such a trade-off wouldn’t be necessary, since the looming budget sequester “is pressure enough” to force both sides to bargain. One thing Kaine does not want to do is put off a resolution to the sequestration issue any further.

“I’m not going to support kicking it down the road,” he said.

Delaney, meanwhile, won a seat on the Financial Services Committee, a natural fit given his background as founder of the Chevy Chase-based commercial lending firm CapitalSource.

Delaney had never held elected office before ousting longtime Rep. Roscoe G. Bartlett (R) from a district redrawn by Democrats to include a portion of Montgomery County.

“I think people were optimistic that there might be something bigger done [on the fiscal cliff], which there wasn’t, so we’re going to be right back at the drawing board,” Delaney said.

The prospect of steep cuts is being watched closely in both Virginia and Maryland. “My district has a lot of people who work for the federal government, and I think they’re very anxious about it,” Delaney said.

Even in his brand new House office, Delaney said he is deliberately “not hiring at the level we need” because Congress — like much of the rest of the government — could face automatic budget reductions in two months.

“I think the sequester will not happen,” Delaney said. “[That] would be my bet.”