'One thing is really critical – taking someone out of the Senate, taking someone out of the House, particularly for a person of consequence, is a really difficult decision that would have to be made,' Biden said during an interview with NBC News' Lester Holt.
'I have a very ambitious, very progressive agenda. and it's going to take really strong leaders in the House and Senate to get it done,' Biden continued in his first interview since he declared victory.
Holt asked Biden if he would welcome any of his former Democratic primary rivals into his administration – specifically pointing to Elizabeth Warren of Massachusetts and Bernie Sanders of Vermont.
'Well, I've talked to them,' the former vice president said. 'We already have significant representation among progressives in our administration, but there's nothing really off the table.'
Biden is cautious about tapping Democratic members of Congress with such a newly narrowed majority in the House. Best case scenario for Democrats in the Senate is 50 seats and the vice president tie-breaking vote.
Tuesday, Biden officially announced many of his Cabinet picks, including several familiar faces – like Barack Obama's second-term Secretary of State John Kerry, who will serve as the U.S. Special Presidential Envoy for Climate.
The former vice president also tapped Avril Haines to serve as his director of national intelligence, after she was already the deputy director of the CIA and then deputy national security adviser under Obama.
He chose Antony Blinken, who was Obama's deputy secretary of state, for his secretary of state.
Biden's staff is inundated with people who have held similar jobs in the past and those who were in line for posts if Hillary Clinton won in 2016.
With the Senate majority still up for grabs, Biden isn't taking any further chances for a split government once he takes office in January by tapping those from Congress for his administration.
So far, Democrats have nabbed 46 Senate seats and Republicans are currently standing at 50 – there are two independents, Sanders and Maine's Angus King, who both caucus with Democrats.
The two Georgia Senate races this election, however, forced a runoff, meaning the future majority in the upper chamber relied on the outcome of those two races.
If Republicans hold onto their majority in the Senate, many of Biden's legislative initiatives will fail.
The Democrat states he and Kamala Harris, who was also once his primary rival, will consider appointing Republicans to his Cabinet.
Holt asked Biden if he would consider appointing a Republican to a key administration role even if they publicly supported and voted for Donald Trump.
'Yes,' he replied. 'We still have a lot more appointments to make. I want this country to be united. The purpose of our administration is once again uniting. We can't keep this virulent political dialogue going. It has to end.'