Sen. Tim Kaine (D-Va.) interrupted Gov. Mike Pence (R-Ind.) repeatedly at the Oct. 4 vice-presidential debate in Farmville, Va. But it didn't always pay off. (Peter Stevenson/The Washington Post)

Since joining the Democratic ticket, Tim Kaine has proved to be a workmanlike campaigner, ably touting Hillary Clinton’s agenda and throwing punches at Republican Donald Trump without damaging his own nice-guy reputation.

At the vice-presidential debate here Tuesday, however, Kaine turned in a performance that threatened to undermine the image of authenticity that has been one of his greatest strengths.

The senator from Virginia came across as over-rehearsed, often interrupting his Republican opponent, Gov. Mike Pence of Indiana, with points Kaine had already made several times earlier in the debate. At times, Kaine simply seemed to be trying too hard.

At one point in the 90-minute encounter at Longwood University, Kaine accused Trump of being someone who “loves dictators” and then unloaded one of many canned lines of the evening, accusing Trump of having “a kind of personal Mount Rushmore: Vladimir Putin, Kim Jong Un, Moammar Gaddafi and Saddam Hussein.”

Pence, who maintained the calmer demeanor through much of the debate, was able to easily parry, asking Kaine: “Did you work on that one a long time?”

Here are key moments from the face-off between Republican vice-presidential candidate Mike Pence and Democratic rival Tim Kaine at Longwood University in Farmville, Va. (Sarah Parnass/The Washington Post)

Some other Kaine lines fell flat as well. “You are Donald Trump’s ‘Apprentice,’ ” Kaine said to Pence early in the debate, referencing the hit NBC show in which contestants sought to earn a position working alongside Trump in his business enterprises.

In other ways, Kaine accomplished what the Clinton team was looking for.

He highlighted key differences between the two tickets on issues including immigration, and he recounted many of the controversies that have done damage to Trump in recent weeks, including his public spat over the weight gain of a Latina beauty queen and his assertion that avoiding income taxes makes him smart.

“I guess all of us who do pay for those things, I guess we’re stupid,” Kaine said, ticking off the government services funded by taxes, including the military.

Often at the pressing of Kaine, Pence also made numerous statements that conflicted with positions of Trump. Pence, for example, suggested that Trump would not immediately deport all undocumented immigrants and that Russia is a dangerous country that must be dealt with aggressively by the United States.

Kaine’s sometimes awkward performance Tuesday night brought back memories of the last time millions of Americans watched him on television — his speech at the Democratic National Convention. On that night, Kaine unleashed a cringe-worthy impersonation of Trump, repeating the phrase, “Buh-leave me” to mock the GOP nominee.

Mike Pence and Tim Kaine sparred over the issue of abortion during the vice-presidential debate at Longwood University in Farmville, Va., Oct. 4. (The Washington Post)

But those prime-time moments stand in stark contrast to the impression he has made on much smaller audiences as he travels among presidential battleground states on Clinton’s behalf. The difference suggests that Kaine, who draws on skills honed over a long political career starting on the Richmond City Council, is still more comfortable in more intimate settings.

On the campaign trail, Kaine has proved versatile, demonstrating an ability to relate with a variety of audiences.

Speaking to African American groups, Kaine has recalled his days as a civil rights lawyer and discussed his membership in a predominantly black Catholic parish in Richmond.

When addressing Latino audiences, Kaine frequently breaks into Spanish that he picked up while taking a break from law school to work with Jesuit missionaries in Honduras.

And the Clinton campaign has also sent him into largely working-class pockets of battleground states, in the hope that his appeal to fellow white men will allow him to vouch for Clinton in a demographic with which she has struggled.

Kaine has a long political résumé that includes stints as Richmond’s mayor, Virginia’s governor and chairman of the Democratic National Committee.

But the role that has in some respects best prepared him for his current venture was the four years he served as his state’s lieutenant governor — another job where his profile was overshadowed by a more prominent political partner, in that case venture-capitalist-turned-governor Mark R. Warner.

During Tuesday night’s debate, Kaine also repeatedly vouched for his running mate, who he referred to most often simply as “Hillary.”

“My primary role is to be Hillary Clinton’s right-hand person and strong supporter as she puts together the most historic administration possible,” Kaine said at the debate’s outset. “And I relish that role. I’m so proud of her.”

Clinton has said she chose Kaine for the ticket because of his ability to help her govern. In addition to his focus on domestic issues as governor, Kaine has gained foreign policy experience through his seats on the Senate Armed Services and Foreign Relations committees.

On the campaign trail, Kaine comes across as more authentic than Clinton, to whom many voters, including those who support her, say seems very distant.

Audience members at Kaine rallies have held signs referring to him as “America’s Dad.” His joint appearances with his wife, Anne Holton — who has referred to the vice-presidential candidate as “my hubby” in front of audiences — has bolstered that image.

Holton, until recently Virginia’s education secretary, is spending plenty of time on the road promoting the Democratic ticket on their own. But when the couple travel together, Kaine has told audiences it feels like they are on vacation together.

The couple have three children, all young adults now, including one whom Kaine confessed last month to an audience in Iowa had voted for Sen. Bernie Sanders of Vermont, Clinton’s rival in the Democratic primaries. It was a line that might not have been good for Clinton but reinforced that notion that Kaine is honest.

Kaine was tagged by some with the “boring” label at the time of his selection in July. But there have been moments on the campaign trail where he’s come across as nothing of the sort.

Three weeks into his service, he whipped out a harmonica during a visit to an Asheville, N.C., brewpub and joined a male-female guitar-and-vocal duo for a rousing rendition of “Wagon Wheel” followed by “My Home’s Across the Blue Ridge Mountains.” After finishing, Kaine bellied up to the bar and ordered a locally brewed White Zombie beer.

Kaine has also showed a sense of humor about the often-scripted nature of campaign events. At an event in Daytona Beach, Fla., after chatting with teachers and students in a culinary school kitchen, Kaine directed the attention of reporters trailing him to some blue arrows taped on the floor, showing him where to exit.

“They make it easy for me,” he said.