Ed Miliband admitted while he wasn't gloomy "things could be a lot better" as he opened his question and answer session with the studio audience.
In a candid exchange with the studio audience, hosted by Sky's Kay Burley, Mr Miliband said the contest in 2010 had been very difficult for his family.
But he said the Labour party had to move away from "New Labour", in which his Blairite brother David was a key player, because it had been too relaxed on inequality and failed over Iraq.
He said: "I thought somebody needed to lead the Labour party who could move us away from New Labour.
Mr Miliband has suffered open attacks in Parliament over his treatment of his brother, while many in the Labour party believe David would have done a better job.
There has been increased speculation that the older brother will return from the US in time to lead the Labour party to victory in 2020.
The Labour leader was asked about his apparent hostility to wealth and told by one member of the audience that she felt bad for having a good job.
Mr Miliband said: "I think the thing that is happening in Britain is it is the very richest in society, I am talking about the top 1%, people earning over 150,000 a year who are doing OK and lots of people, including on middle incomes are finding life tough.
"The question is how we do something about it."
Mr Miliband had chosen to take to the stage second and followed David Cameron.