The face-to-face clash between the two White House rivals on Wednesday granted an unexpected 15 minutes of fame to Mr Joe Wurzelbacher, 34.
Until Sunday, when he bumped into Mr Obama while the Democrat was doing door-to-door canvassing, Mr Wurzelbacher was living a normal, low-profile life.
But his encounter with Mr Obama in Toledo, Ohio, and a spirited debate about the front-running Democrat's tax policy, turned him into a media star.
Both candidates spoke directly to Mr Wurzelbacher during their third and final debate, turning him into a real-life version of 'Joe Six Pack', the ordinary guy chasing the American dream.
'Joe wants to buy the business he's been in for all these years,' Mr McCain said, using Mr Obama's encounter with the plumber to flay his rival over a tax plan he claimed would shackle small businesses. 'But he looked at your tax plan and he saw he was going to pay much higher taxes.'
Mr Obama said his tax plan will mean lower taxes for those earning less than a quarter of a million dollars a year, and hit back with his version of his chat with Joe.
'What I essentially said to him was, five years ago, when you were in the position to buy your business, you needed a tax cut then. And what I want to do is to make sure that the plumber, the nurse, the firefighter, the teacher, the young entrepreneur who doesn't yet have money, I want to give them a tax break now.'
Not to be outdone by the candidates, Plumber Joe got in on the act himself, granting various media interviews.
He told CBS that Mr McCain did a 'fine job' and said Mr Obama did well too, though he added that the Democrat had dodged around his question about taxes when they met. 'I asked the question, but I still got a tap dance...'
But he wasn't about to divulge his choice for president. 'It's a personal decision, and myself and the button I push will know the answer,' he said on ABC's Good Morning America show.
AGENCE FRANCE-PRESSE, REUTERS