"Not only do their different backgrounds and career paths bring distinctive and important perspectives to the court, Bruce and Phil also capture the state's diversity," he said.
Neither has previously served as a judge. Their confirmations would leave the court without a justice from South Jersey.
Harris, 61, would be the third African American justice to serve on the court and the nation's seventh openly gay state justice. He was accompanied at Monday's news conference by his longtime partner, Marc Boisclair.
"This is an important moment in our state's history and in our country's history and signals just how far we have come," the Republican governor said.
The announcement came a day before the Democratic Legislature was to begin hearings on a bill that would allow same-sex marriage. Christie has expressed opposition to same-sex marriage in the past, and strongly indicated Monday that he would veto such a measure.
"I'm not somebody who changes positions with the grace of a ballerina, so I wouldn't be all atwitter in expectation," he said.
Christie has expressed his intention to remake the court, whose justices he has blasted for their mandates on affordable housing and state funding for poor school districts.
He said he did not ask the nominees about specific cases but inquired about their experiences in the courtroom and legal philosophies.
Democrats and the NAACP had pressured Christie to appoint minorities to what had become an all-white court.
In 2010, for the first time in the history of the modern court, Christie denied tenure to a Supreme Court justice, John Wallace, who is African American and a friend of Senate President Stephen Sweeney (D., Gloucester).
That led to a yearlong impasse in the Senate over Christie's replacement, Anne Patterson. She was ultimately sworn in to replace Justice Roberto Rivera-Soto, who did not seek reappointment after objecting to an interim measure to fill Wallace's spot.
With the departure of Wallace and Rivera-Soto, Christie said diversity was an important criterion in choosing nominees. But, he said, it was not the primary factor.
On Monday, he quoted Sweeney's exhortations for diversity on the seven-member bench. The implication was that if Sweeney were sincere, Kwon and Harris should sail through the confirmation process.
"As with all nominees, the process must still run its course," Sweeney said in a statement. "While we undergo that process, it is vital that we ensure the Court remain as philosophically independent as possible."
Harris and Kwon would replace Wallace and Justice Virginia Long, who faces mandatory retirement at age 70. If confirmed, they could be seated as early as March.
Kwon, 44, of Closter, Bergen County, is the top adviser to the state attorney general. Though unaffiliated politically, he is a longtime associate of Christie. Kwon recently led a committee intended to strengthen rules so police and firefighters do not use their publicly funded health plans to abuse steroids.
Kwon would become the first immigrant on the court, "recognizing an important cultural and ethnic piece of our state's makeup," Christie said.
"This is a deep honor for me, for my family," Kwon said in brief remarks.
Harris was a manager at AT&T before graduating from Yale Law School as an older student, according to his LinkedIn profile. He was elected mayor of Chatham, Morris County, in November, after serving as councilman.
The Iowa native, the oldest of a dozen children, thanked his partner, Boisclair, "for his nearly 32 years of love and support even when I decided to change careers and attend law school, which meant that for three years we were apart for extended periods of time."
Christie called Steven Goldstein, president of the gay-rights group Garden State Equality, shortly before his announcement to tell him of Harris' nomination.
"As I told the governor right then and there, you could have picked me up off the floor," Goldstein later said in a statement that praised Christie's "warmth and responsiveness" in dealing with the gay community.
Harris' colleagues on the Chatham Borough Council called him fair and erudite.
"He always makes judgments on the facts, he never lets emotions get involved," Councilman John Holman said Monday.
Council President Jim Lornegan, Harris' running mate, called him a "commonsense guy" who is more "detail-driven" than anyone on the council.
Christie said at the news conference that he had not met Harris before interviewing him last month, causing Harris to interrupt and recall their meeting at a town hall.
"I thought I made an impression," Harris joked.
Contact staff writer Matt Katz at 609-217-8355, firstname.lastname@example.org, or @mattkatz00 on Twitter. Read his blog, "Christie Chronicles," at philly.com/christiechronicles