A short time later in court, his defense team - whom he described as "excellent because they believe deeply in my innocence and are personally committed to me" - went to work at challenging the credibility of the prosecution's key witness, Jonnie Williams, the former CEO of Star Scientific Inc.
In testimony Monday, one of McDonnell's closest confidantes made it clear that he didn't have much regard for Williams - the wealthy businessman - who, according to prosecutors, bought the influence of the governor and his wife to benefit the nutritional supplements company he headed.
Bob and Maureen McDonnell are charged in a 14-count indictment with accepting more than $165,000 in gifts and loans from Williams, in exchange for their help promoting his company's products. Williams testified under immunity that he was not friends with the McDonnells and only plied them with designer clothes, vacations and secret loans so they would help him.
Phil Cox, who managed McDonnell's 2009 campaign and later ran his political action committee, testified that he aired his concerns after he noticed Williams frequently hanging around the McDonnells - particularly Maureen, who Cox also expressed little regard for.
"(Williams) definitely raised some red flags for me," said Cox, now executive director of the Republican Governors Association. "I thought he was a little bit of a snake oil salesman."
Prosecutor David Harbach asked if he thought Williams, who often loaned his private jet to the McDonnells, wanted something from the governor.
"A lot of donors are looking for something," Cox said.
He also testified that in 2012, Williams and Maureen McDonnell tried unsuccessfully to get a meeting with GOP presidential candidate Mitt Romney to pitch Star Scientific's signature product, the anti-inflammatory Anatbloc. McDonnell had just endorsed Romney and was being mentioned as a possible running mate.
Having failed to get an audience with the candidate, Maureen McDonnell cornered his wife, Ann Romney, on a campaign bus and began telling her how Anatabloc could cure her multiple sclerosis, Cox testified.
"I was horrified," Cox said. "I didn't think it sort of showed the governor in a great light."
Cox also said he got an email from an angry Maureen McDonnell on Christmas eve 2009, after he had advised against Williams buying an inauguration dress for her.
"It was sort of an insane rant of an email," Cox said. "Coming on Christmas eve, it angered me."
Asked by Bob McDonnell's attorney his opinion of Maureen, Cox said: "When she was happy she could be very sweet and caring. When she was unhappy she could be very difficult and mean."
He expressed a much higher opinion of the former governor, saying he "tends to think the best of everybody."
Asked by the defense attorney if McDonnell ever seemed to crave money and fine things, Cox said: "He's like the least materialistic person I know."
Cox was the first witness to testify after Williams, who spent much of four days on the stand detailing his spending on the McDonnells in an attempt to get them to attend promotional events and help him obtain grants for further study of Anatabloc. No grants were awarded, but the McDonnells attended several events and hosted the Anatabloc product launch at the governor's mansion. The governor's PAC paid for that event, Cox testified.
Williams testified Monday that he never saw any signs the governor's marriage was crumbling, and that he never had any intimate physical contact with the first lady.
A defense attorney said last week that the first lady, feeling neglected by her frequently absent husband, had developed a crush on Williams and that he had led her on - suggesting, perhaps, that the McDonnells could not be conspiring to obtain gifts and loans from Williams because they were barely communicating.
"I didn't know she had any interest in me until this past week," Williams sheepishly said on the stand.
Assistant U.S. Attorney Michael Dry asked specifically whether Williams and Maureen McDonnell had any intimate contact.
"I never had any contact with Mrs. McDonnell - no physical contact, period," he said.
Williams also said Maureen McDonnell never told him her marriage was on the rocks, and he saw no signs that it was. To further make the point, the prosecution showed two photos of the McDonnells at public events. They were holding hands in one, and Bob McDonnell was kissing his wife on the cheek in the other.
Defense attorneys last week noted that Williams and Maureen McDonnell had exchanged text messages and phone calls more than 1,200 times in less than two years, suggesting that the relationship between Williams and the McDonnells was not strictly business as Williams has said. Dry put that number in context, though, by mentioning Monday that during the same period Williams made or received about 109,000 calls and texts.
"I'm a busy man," Williams said.
Asbill asked Williams whether having the governor call the businessman's father on his 80th birthday was business or personal. Williams said it was personal, but it wouldn't have been possible without his spending on the McDonnells.
"This cost me, in my mind, hundreds of thousands of dollars even to be able to do that," he said.
Bob McDonnell's attorney, Henry Asbill pursued a line of questioning aimed at pinning most of the requests for gifts and loans on Maureen McDonnell and suggesting that the governor did little, if anything, for Williams in return. Williams acknowledged that his company received no state grants, which is what he was after.
But he pointed to a gathering of health care leaders at the governor's mansion, where Williams was permitted to invite anyone he wanted for a discussion about Star's signature product, Anatabloc.
"That was a very significant evening, to have that sort of thing happen for my company," he said.
Among the gifts Bob McDonnell received was a Rolex watch purchased by Williams and given to the governor by his wife for Christmas 2012. Williams received a text message that Christmas Eve with a photo of a smiling McDonnell showing off the timepiece.
"My first thought was I was scared to death," Williams said of his reaction to seeing the picture. "It's the first time I'm sure he knew it came from me."
Williams testified last week that Maureen McDonnell asked him to buy the watch, and it was a mistake to do so.
Asbill, attempting to undermine Williams' credibility, questioned Williams about his immunity agreement. He reminded Williams that he testified that a company's first responsibility is to stay in business.
"Would you agree the second rule of business is not to go to jail?" Asbill asked.
Williams, who has said repeatedly that he has done wrong, replied: "I don't think any businessman wants to go to jail."
Asbill, also challenged Williams' credibility by questioning him about lawsuits he and Star faced over allegations of securities violations. Williams said he thought most of the half-dozen "nuisance suits" by Star shareholders had been settled or soon would be, but Asbill noted that two were put on hold at the request of prosecutors in the McDonnell case.