Ms. Kelly testified that she discussed the shutdown with the governor before and while it was happening. And the governor’s chief political strategist acknowledged on the stand that Mr. Christie had lied at a December 2013 news conference when he said that senior members of his staff and his campaign chief had assured him they were not involved.

Facing about 50 reporters and television cameras outside the federal courthouse here on Friday, the United States attorney for New Jersey, Paul J. Fishman, said that his office brought charges against only the people it believed a jury would find guilty beyond a reasonable doubt. There was substantial documentary evidence, he said, to corroborate Mr. Wildstein’s testimony about Ms. Kelly and Mr. Baroni, once Mr. Christie’s top staff appointee at the Port Authority.

“We don’t say we have sort of enough, let’s throw it against the wall and see what the jury does,” Mr. Fishman said. “That’s not our job.”

Mr. Christie issued a statement shortly after the verdicts were delivered, again denying any role in the lane closings. “Let me be clear once again,” he said. “I had no knowledge prior to or during these lane realignments, and had no role in authorizing them. No believable evidence was presented to contradict that fact.”

Mr. Fishman, who succeeded Mr. Christie as the United States attorney for New Jersey, declined to specifically address the governor’s comments but pointedly expressed confidence in Mr. Wildstein’s testimony that the governor had been told about the plot.

“When we put witnesses on the stand, we put witnesses on the stand who are corroborated by other evidence,” he said. “And we don’t ask people to testify about things when we think they might not be true.”