During the general election, Vice President-elect JD Vance made it clear that he was the policy attack dog and one of the primary messengers for Donald Trump's campaign. Now his vice presidential responsibilities are taking shape, with expectations that he will be Trump's "eyes and ears" in Congress, a source told ABC News.

Leading up to the election, Vance kept a busy schedule that was a mix of campaign events and vast media appearances, including TV interviews, sitting down for digital interviews, and appearing on some of the world's most listened-to podcasts.

During his election night speech, Trump called his running mate "feisty" and praised his work on the campaign trail.

But as Vance enters his new role, a source familiar told ABC News that we should expect him to play a different role than the one we've become accustomed to over the past nearly four months.

Vance has been tasked to ensure that all of the priorities of the Trump administration move forward and will work on any of the issues Trump needs him to further, a source familiar told ABC News, signaling that Vance will not be assigned one specific issue to work on, but will be involved in several policy issues.

Some of the policy issues Vance could be dispatched on include the economy and immigration, which were the core issues Trump ran on during his campaign, the source said.

It's also expected that Vance will be Trump's "eyes and ears" in the Senate to ensure that his agenda moves forward, the source also said.

It's familiar territory for Vance, who was elected to the Senate in 2022. When Vance is sworn in as vice president in January, he will be the youngest vice president in modern American history and will be entering the office with a very brief political portfolio, having just those two years in the Senate as the first political office he ever held.

Vance will also be succeeding Trump's last vice president, Mike Pence, who broke with Trump when it came to accepting the results of the 2020 election and refused to concede to the pressure from Trump not to certify the election results.

Vance has shown to be different from Pence, remaining steadfast in his loyalty to the president-elect and defending him at every turn, something he spoke on before becoming Trump's vice presidential pick. Still, Vance once made clear his disdain for Trump, saying he was a "never-Trump guy" in an interview with Charlie Rose in 2016.

A source familiar with Vance and Trump's relationship said Vance is focused on doing whatever is needed to support the president-elect and the administration.

"So, whether that means focusing on a specific policy issue or serving as his hammer to get things across the finish line in the Senate, JD is ready to deliver for the president," the source told ABC News. "They've built a close personal friendship over the past few years and because of that, have a lot of trust in each other."

In June of this year, Vance spoke at a Turning Point event where he was asked what Trump needed in a vice president and Vance said someone who is "not trying to stab him in the back."

"There are a lot of smart, good people that Trump is looking at, but it also applies to our senators. It applies to our congressmen and women too. We need to have people who are supporting Trump -- not trying to stab him in the back. It's very, very simple," he said.