Shadow energy secretary Caroline Flint dismissed suggestions that Mr Miliband was seen as too "weird" to become Prime Minister, saying his "authenticity" was one of his major assets.
Speaking on BBC One's Sunday Politics, she said: "Ed is part of Labour's success, definitely, in the last few years."
Ms Flint said it was "ridiculous" 13% of people saw him as weird, saying where voting's concerned, people would be more interested in the cost of living crisis.
She said: "To be fair to Ed, Ed is not a politician who says: 'Do you know what? I'm down with the Arctic Monkeys, I know who's number one.'
"He doesn't try to play that game. He goes on Desert Island Discs and says he likes A-ha. He's not out there to try and portray himself as someone that's down with the kids, 'I know everything about popular culture'; he is who he is, and authenticity is the most important."
Meanwhile, East Renfrewshire MP and shadow international development secretary, Jim Murphy - who was demoted from the defence brief when Mr Miliband reshuffled his frontbench team last year - said Labour's leader had been successful in preventing the party tearing itself apart after the 2010 election defeat.
"Ed Miliband has delivered a united Labour Party which is unlike all the historical experience of the Labour Party, where we usually form a circular firing squad against each other when we lose an election," he said.