Northam received 53.9 percent of the vote to Gillespie's 44.9 percent in Virginia, with over 99 percent of precincts reporting, as of 10:30 p.m. EST. Murphy attained 55.3 percent of the vote in New Jersey to Guadagno's 42.7 percent with over 88 percent of the state's precinct's reporting, as of 10:30 p.m. EST.
The Virginia race, in particular, took on the air of a referendum on Trump throughout the campaign. The commonwealth's status as a swing state in presidential years and the stark divide between its suburban northern region and rural Appalachian southwest turned it into a representative test case on the country's response to the two major political parties a year after electing the former real estate mogul.
Though Trump had not personally campaigned for the Republican in Virginia, Northam’s campaign attempted to tie the president to Gillespie, banking on Trump’s unpopularity in the commonwealth to help secure the fourth gubernatorial victory for Democrats in the past five Virginia races.
Northam continued by pledging to "put the people of Virginia before politics, before party and before ideology," and by noting the increasing diversity of the U.S. and of the commonwealth. He said that his administration will endeavor to make Virginia as welcoming a place as possible.
"Our lights will be on, our doors will be open," he said.
Trump reacted to the result in Virginia via Twitter from South Korea, where he is in the midst of a 13-day trip, writing that "Gillespie worked hard but did not embrace me or what I stand for."
Trump’s firebrand former chief strategist Steve Bannon -- who had stumped for successful Alabama Republican primary candidate Roy Moore in September -- offered to rally for Gillespie on multiple occasions but the campaign rejected his offer, according to two sources close to Bannon.
Breitbart, the ultra-conservative website that Bannon helped found, published stories supportive of Gillespie, which political observers saw as a sign of Bannon’s interest in the campaign. But two sources close to Bannon said he was always skeptical of Gillespie’s commitment to the Trump agenda which only started to play up in the final weeks of the campaign.
Bannon made it known that he was concerned about Gillespie’s lack of energy and his close association with George W. Bush via his service as a White House adviser.
“Ed Gillespie had no coherent message, was inauthentic, spoke from both sides of his mouth and at the end of the day, even the deplorables couldn’t save him,” Andy Surabian, former Trump White House staffer and political adviser to Bannon, told ABC News.
A Gillespie spokesperson did not immediately respond to a request for comment.
"Starting here, and starting with us, New Jersey is coming back," Murphy said, before pledging to put together a diverse administration that reflects the population of the state.
"We will rebuild our state from the bottom up, and from the middle out," he added.
Trump was notably quiet on the race in the traditionally blue state where Murphy led Guadagno by consistent double-digit margins in polls ranging back to the spring. Recent polls showed the Democrat with a lead of between 10 to 15 points.
Surveys of Virginia voters showed a markedly closer race, with Northam out-polling Gillespie by as many as 9 percentage points in one poll, while falling within the margin of error in another.
ABC News' Tara Palmeri contributed to this report.
Look back at updates from earlier in the day below: