The Ehrlich campaign rejected the plan but continued to pay Henson $16,000 a month — for a total of $112,000 — and promised him a $30,000 bonus should Ehrlich win.
Jurors also said they didn't accept arguments that the call was protected free speech.
Lester Spence, an assistant professor of political science at the Johns Hopkins University, said he believed Ehrlich's legacy could be hurt by the jury's verdict.
"If this were a state that bled red, he'd be all good," Spence said. "Maryland is a state that is so Democratic, there's no way he can spin it. His legacy should be tainted, but those people who believe he was a great governor are still going to believe that."
After the verdict, Davitt told reporters that the case was not politically motivated. He noted the investigation into the robocall began under the his predecessor, Robert A. Rohrbaugh, who was appointed by Ehrlich.
"If it's the Democratic Party, the Republican Party or the Communist Party, this type of behavior will not be tolerated in the future," Davitt said.
Democrats immediately celebrated the jury's verdict.
"The right to vote is precious and a critical part of our democracy. Paul Schurick and the Ehrlich campaign sought to take away that right for some of our fellow citizens," Maryland Democratic Party Chair Yvette Lewis said in a statement.
On Friday, Schurick took the witness stand in his own defense and admitted he approved the text for the automated phone call, but said it was not intended to suppress black votes.
The automated call said O'Malley and President Barack Obama, who was not on the ballot, had been "successful" in that day's election. The robocall told voters that "our goals have been met. The polls are correct, and we took it back. We're OK. Relax. Everything's fine. The only thing left is to watch it on TV tonight."
During a hearing last week while the jury was not in the courtroom, the presiding judge in the case, Lawrence P. Fletcher-Hill, told lawyers he believed the call was "plainly fraudulent" and one needed only "common sense" to see that the call was "an attempt to try to get people to stay at home."
The jury —five black women, two black men, three white women and two white men — spent about five total hours deliberating before returning the verdict around noon.