The races' final days were overshadowed by the death of U.S. Sen. Frank Lautenberg and Christie's decision, on primary day, to announce an October special election to fill the seat rather than have the contest coincide with the Nov. 5 general election.
Christie sought to build bipartisan appeal ahead of the primary, looking to score a blowout win in November, which could set him up for a presidential run in 2016.
Buono, meanwhile, looked to cast doubt on the governor's claims New Jersey's economy has turned around, focusing attention on the state's continuing high unemployment and high property taxes.
"Our problem, my friends, is a governor who sees 400,000 people out of work and he tells us everything is just fine," she told supporters in Edison as she accepted her party's nomination.
She also used her speech to attack Christie's leadership style, saying it was time to put an end to "the era of mistaking name-calling for consensus-building."
Christie was to speak later in the evening to supporters in Bridgewater.
"Republicans love this governor, they want to come out and support him. They can't wait to see him re-elected and maybe win one or both houses of the Legislature," said Bill Palatucci, an adviser to Christie. "I find the enthusiasm is really high."
The race has been a fundraising mismatch.
The governor, his popularity soaring to record highs for his handling of Superstorm Sandy and the ensuing recovery, raised $6.5 million before the primary, enough to produce TV ads in English and Spanish and air them in the pricey New York and Philadelphia media markets.
Buono, despite having held positions as state Senate budget committee chair and majority leader, has struggled to gain name recognition and campaign cash. She raised $2.3 million with the help of public campaign financing, but fell shy of the maximum amount she could have received had she gotten more private donors. With so little cash on hand, she had to turn to YouTube videos and meet-and-greets to get word out about her campaign.
Christie voted in Mendham with his wife, Mary Pat, and 20-year-old son. Buono cast her ballot in Metuchen.
Voter participation in primaries is traditionally low. In the last gubernatorial primary in 2009, 11 percent of the 5.2 million eligible voters cast ballots.
Christie was opposed by Seth Grossman, formerly an Atlantic City councilman and Atlantic County freeholder, who claimed Christie was too moderate. Buono was opposed by Troy Webster, an aide to the mayor of East Orange.
The state has 700,000 more registered Democrats than Republicans.
All 120 seats in the Legislature are up for election in November, but only 20 had contested primaries.
Some of the most-watched races were Democratic primaries for state Senate in Union and Essex Counties. The incumbents won easily in both.
In Union, Sen. Ray Lesniak withstood a challenge from Roselle Board of Education president Donna Obe. In Essex, Sen. Nia Gill beat Seton Hall Law School professor Mark Alexander.
In Atlantic City, Christie nemesis Lorenzo Langford, the Democratic mayor, beat two challengers - Atlantic County Freeholder Charles Garrett and David Davidson Jr., the retired former head of the city police union.
AP reporters Geoff Mulvihill in Trenton and Rema Rahman in Edison contributed to this report.