Updated: 6:35 p.m. ET
(AP) GREENSBORO, N.C. -- Andrew Young was once much more than an aide to John Edwards.
Young spent long hours driving to and from political events with the two-time Democratic presidential candidate. They went to basketball games together to root for the Tar Heels and buddied around at Edwards' beach house. Young was even tasked with buying Christmas presents for the Edwards children.
"We were just North Carolina boys and had a lot in common," Young testified Monday.
And when Edwards' mistress got pregnant in 2007 amid a presidential campaign, Young falsely claimed paternity of his boss' child and invited the woman, Rielle Hunter, to move into his Chapel Hill home with his wife and children.
Young was the first witness called by prosecutors Monday following opening statements in Edwards' criminal trial. His testimony is expected to be the lynch pin of the government's case that Edwards masterminded a conspiracy to use nearly $1 million in secret payments from two wealthy donors to help hide his pregnant mistress as he sought the White House in 2008.
Edwards, 58, has pleaded not guilty to six criminal counts related to alleged violations of federal campaign finance laws.
"It wasn't just a marriage on the line," prosecutor David Harbach said in his opening statement. "If the affair went public it would destroy his chance of becoming president, and he knew it. ...He made a choice to break the law."
U.S. District Court Judge Catherine C. Eagles seated 12 jurors and four alternates Monday morning. The panel is made up of nine men and seven women drawn from central North Carolina. Edwards represented the state for one term in the U.S. Senate.
Edwards stared intently at Young as his former confidant testified. In nearly two hours of talking about Edwards, Young never looked in his direction.
For Edwards' defense team, destroying Young's credibility is key to their strategy of keeping the former presidential contender out of prison.
They allege that much of the money at issue in the case was siphoned off by Young and his wife to pay for a $1.5 million house finished in 2008.
"Follow the money," defense lawyer Allison Van Laningham urged jurors in her opening statement. "John Edwards did not get any of this money. Not one cent."
Edwards' lawyers contend the payments were gifts from friends intent on keeping the candidate's wife from finding out about the affair. Elizabeth Edwards died in December 2010 after battling cancer.
A key issue will be whether Edwards knew about the payments made on his behalf by his national campaign finance chairman, the late Texas lawyer Fred Baron, and campaign donor Rachel "Bunny" Mellon, a now-101-year-old heiress and socialite. Each had already given Edwards' campaign the maximum $2,300 individual contribution allowed by federal law.
Edwards denies having known about the money, which paid for private jets, luxury hotels and Hunter's medical care. Prosecutors will seek to prove he sought and directed the payments to cover up his affair, protect his public image as a "family man" and keep his presidential hopes viable.
On the witness stand Monday, Young recounted how he met Edwards in 1998, as the Raleigh trial lawyer and political neophyte was campaigning for the Senate.
"My father was a minister, so I had seen a lot of great speakers," Young recounted. "He was really `on' that day."
Young said he immediately told his future wife, Cheri Young, that Edwards had the potential to become president and that he wanted to work for him. Young quickly rose from a junior campaign staffer to working on the senator's North Carolina staff following the election. When no one else wanted to pick up Edwards at the airport, Young leapt at the opportunity. He eventually took the title of special assistant to the senator, a gatekeeper of who got phone calls and face time with Edwards.
Young also testified about first meeting Hunter as she travelled with Edwards in 2006. Also that year, Young first spoke with Mellon and put her in touch with Edwards.
Young is set to resume his testimony Tuesday.
Young and his wife later invited the pregnant Hunter to live in their home near Chapel Hill and embarked with her on a cross-country odyssey as they sought to elude tabloid reporters trying to expose the candidate's extramarital affair.
Young eventually fell out with Edwards and wrote an unflattering tell-all book, "The Politician." Young and Hunter recently ended a two-year legal battle over ownership of a sex tape the mistress recorded with Edwards during the campaign, agreeing to a settlement that dictates that copies of the video will be destroyed.
Two of the lawyers who represented Hunter in her civil suit against the former aide joined Edwards' legal team last month. After years of adamant public denials, Edwards acknowledged paternity of Hunter's daughter, Frances Quinn Hunter, in 2010. The girl, now 4, lives with her mother in Charlotte.
It has not yet been decided whether Edwards, a former trial lawyer once renowned for his ability to charm jurors, will testify in his own defense.
Before the jury entered the court room Monday, Eagles disclosed that Young had called three other witnesses in the last two weeks. Eagles ruled that lawyers for Edwards could mention the improper contact to jurors in opening statements Monday, but barred them from using the term "witness tampering" or telling the jury that Young had a one-night stand with one of the other witnesses in 2007.
Eagles, who was appointed in 2010 by President Barack Obama, said she expects the proceedings to last about six weeks.