(CNN)Chuck Schumer arrived for his first day as Senate Democratic leader to a large, new Capitol suite still strewn with unpacked boxes.
Chuck Schumer: Trump opposition leader
"It's a little fancier than I'm used to, but it goes with the territory," Schumer told us, as he sat down for his maiden television interview as the Senate's top Democrat.
Schumer was hoping to be the new Democratic Senate majority leader, working with Hillary Clinton in the White House. Instead, he is leading the Trump opposition. The former would have been more fun, he conceded, but he says being minority leader now is "more important."
Here's how he described a recent phone conversation with Donald Trump: "I said, 'Mr. President-elect, you went after both the Democratic and Republican establishments when you ran; you were an anti-establishment change candidate. But by your Cabinet picks and your early pronouncements, you seem to be embracing your timeworn, shop-worn hard right,'" he recalled.
"If you do that, your presidency will not come close to being a success," he told Trump.
For Schumer, success will be even more complicated. He has to walk a very fine line between when to work with Trump, and when to oppose him. Schumer describes it as "accountability."
"The only way we're going to work with him is if he moves completely in our direction and abandons his Republican colleagues," Schumer said.
"90-95% of the time, we'll be holding his feet to the fire, holding him accountable. But we're Democrats, we're not going to just oppose things to oppose them," he added.
Schumer started his congressional career in the House in 1981, and served there until successfully defeating longtime Republican Sen. Alfonse D'Amato in 1998.
He climbed the Democratic ranks as a fierce partisan and prolific fundraiser, but in recent years turned his attention to also becoming a successful legislator who can work across the aisle. He played a key role in crafting bipartisan Senate immigration reform in 2013, though the bill stalled in the House and never became law.
Schumer loves being the center of deal making, a lot like the incoming president.
"Well, here's the problem. The Republicans in the Senate and the House have been run by a hard right group," said Schumer.
But what about now that they have a dealmaker in the White House?
"Look, we're going to look at the specifics," Schumer said. "And on the overwhelming bunch of it, particularly given who he's chosen as his Cabinet people, we're going to have to oppose him because we just disagree in principle."
"Of course I'd like to make a deal," he added.
Many progressives scoff at the notion of Schumer even considering any form of compromise with Trump.
Democracy for America, a leading progressive group, said: "Democratic leaders from Chuck Schumer down need to stop playing footsie with Trump and pretending we can find."
Schumer's response: "We're playing no footsie. My views are exactly the same as Elizabeth Warren and Bernie Sanders."
"If we can work with him and be true to our principles, we're not going to reject him. But overall, we're sticking to our principles," he said.
The two New Yorkers have a history. Schumer says he doesn't know Trump well, but he was one Schumer's of early political donors. Schumer confirmed New York Post reporting that the President-elect told him he likes him better than GOP leaders.
The new Democratic leader said he wasn't surprised, but also not flattered.
"When you get to be in my position, people do tend to want to flatter you and you've got to take it with a grain of salt," he said.
Trump is hardly Schumer's only concern. He's also going to be the de facto leader of the movement to fix the defeated Democratic Party.
"What we have to do is look at this election in the eye and see what we did wrong. I think we know what we did wrong. We have always been a party with a sharp-edged economic message that talks about helping the middle class and people who want to get to the middle class get there more easily. We didn't have that in this election," Schumer said. "So that even though Trump's positions were much further away from where the middle class is and what they want, he seemed to be the person talking to them."
The New York Democrat says he will help his party craft what he calls a "focused and sharp-edged message."
"And here's the good news. Some people say, 'Which direction do you go in? The old Obama coalition or the new blue collar?' If we have a sharp-edged economic message, it unites our party. It unites Joe Manchin (a West Virginia moderate) to Bernie Sanders (a Vermont liberal), both of whom are on my leadership team," Schumer said.
"It unites the blue-collar worker in Scranton, Pennsylvania, the college student paying her loans in Los Angeles, the single mom in Harlem who's on minimum wage," he said, seeming to take the message for a test-drive.
It may be just the task for the man who put himself on the political map in the1980s by being media savvy. It was then that he realized that Sundays were a great day to make news (especially the New York Times), so he started holding regular Sunday news conferences.
In the 1990s, one of the running jokes in Washington was that the most dangerous place in to be in the District was between Schumer and a television camera (Schumer says it was originally former Senate Majority Leader Bob Dole's line after Schumer used his publicity prowess to push through the Brady gun law).
But that's no longer true. Over the past several years, Schumer has tried to be more disciplined. He's more likely to either be on his cell phone in the Capitol hallways, or pretend to be, in order to avoid talking to reporters
"In the early days, the press was a very good way to bring out problems that needed to be fixed. Now, I have other levers of power, so I'm hardly inaccessible. And you can say a lot of bad things about Chuck Schumer and accessibility is never going to be one of them," Schumer said with a knowing laugh.
The same goes for authenticity. Though he proudly declared that he bought a new suit for his first day as leader, he is clearly still the same rumpled guy who slept for 30-plus years on a mattress next to the kitchen in a rundown group house owned by former Rep. George Miller.
He now lives in an apartment, which is why he told us he is excited to have a large balcony outside his Capitol office.
"We're going to try to find out if we can have barbeques," Schumer said with genuine excitement.
After a few more minutes, the New Yorker told us he had to get back to work. After all, he laughed, he can't spend all his time doing press.