PORTSMOUTH, N.H. — New Jersey Gov. Chris Christie plans to issue a statement Wednesday afternoon suspending his presidential campaign, The Washington Times has learned.

The announcement follows a disappointing sixth-place finish in New Hampshire’s first-in-the-nation primary, where Mr. Christie was hoping a strong showing would give him more breathing room in a race where the tough-talking governor competed with former Florida Gov. Jeb Bush, Ohio Gov. John Kasich and Sen. Marco Rubio of Florida to emerge as the most viable alternative to businessman Donald Trump and Sen. Ted Cruz of Texas.

Mr. Rubio carried momentum into New Hampshire following a strong third-place showing in the Iowa caucuses, while Mr. Christie essentially ceded the state, finishing in 10th place.

Mr. Christie’s most memorable moment of the campaign came over the weekend in the eighth GOP debate in which he landed hard blows against Mr. Rubio for being too scripted and too inexperienced to be president, warning that President Obama should serve as a cautionary tale about what happens when the nation elects a first-term senator.

Voters here said that debate led them to rethink their support of Mr. Rubio and give Mr. Christie another look.

The results Tuesday, though, were not good enough to keep the Christie campaign afloat.

Mr. Trump won with 35.3 percent of the vote, followed by Mr. Kasich, 15.7 percent; Mr. Cruz, 11.7 percent; Mr. Bush, 11.1 percent; Mr. Rubio, 10.5 percent; and Mr. Christie, 7.4 percent.

Mr. Christie was polling poorly ahead of South Carolina’s Feb. 20 primary and Nevada’s Feb. 23 caucuses. So it is unclear just how much his exit will impact the race.

The news of Mr. Christie’s pending exit sparked some grumbling from the Rubio camp.

As reports of Mr. Christie’s decision were surfacing, Rep. Trey Gowdy, South Carolina Republican, said the New Jersey governor effectively boosted the Democrats with his attack on Mr. Rubio.

“What Chris Christie did was an in-kind contribution to the Democrat party,” Mr. Gowdy, who has endorsed Mr. Rubio, said on Fox News. “There was no chance that Chris Christie was ever going to be our nominee, and he’s certainly not going to do well in South Carolina if he bothers to come.”

“Marco Rubio can win in November,” Mr. Gowdy said. “In fact … he’s more likely to win than any of our other candidates. So what Chris Christie did is just hurt Marco Rubio. But he didn’t help himself, and in the process he helped whoever the Democrat nominee is.”

Mr. Christie entered the race with high hopes that his “Tell It Like It Is” style would resonate with voters, but he spent months rebuilding his image in the wake of the “Bridgegate” scandal and, like others, struggled with the way in which Mr. Trump sucked all the oxygen out of the room.

Mr. Christie received a bump in the race here in late November after receiving the backing of the Union Leader, the state’s largest newspaper, and closed out the year running third in the polls behind Mr. Rubio and Mr. Trump.

It helped put a bull’s-eye on his back.

The pro-Rubio Conservative Solutions PAC slammed his economic record in New Jersey and the pro-Bush Right to Rise USA PAC dinged him over his decision to expand Medicaid under Obamacare.