Ferrell told Long Island Press that he found the famous leaked video footage of Edwards having his hair elegantly styled a natural target for satire.
"I literally wanted John Edwards's hair. You know, that 'I Feel Pretty' video, where he's combing his hair over. Incessantly," he quipped.
"I mean, just the image of the politician with the perfect hair. And those $900 haircuts, and things like that. It was kind of inspirational to me!"
Ferrell also said he was anxious to spoof the outrageousness of political attack advertisements in The Campaign.
"I enjoyed making fun of the attack ads that are out there. And in terms of the character I got to play, it was really kinda fun debating and giving speeches that literally, when you walk away after listening to them, they mean nothing," he explained.
"But that game was so much fun. Because it's really fun to spend as much time as you can talking about nothing. And seeing how much time you can waste. Which I think they do. A lot of!"
The Campaign's director Jay Roach recently admitted he was surprised by Ferrell and Zach Galifianakis's on-screen chemistry.
The movie is now playing in the US and opens in UK cinemas on September 28.