Jo Swinson was forced to resign as leader when she lost her East Dunbartonshire seat at the general election, having begun the party's campaign with the claim that she could be the next prime minister.
Sir Ed, who was Lib Dem deputy leader, and party president Sal Brinton are joint acting leaders until a leadership election in the new year.
He added: "Let me help you: I'm not ruling it out."
Sir Ed was a hopeful in the last leadership contest, held only six months ago when Sir Vince Cable stepped down.
It saw Sir Ed and Ms Swinson - the only two contenders - face a postal ballot of the party's membership, with Ms Swinson beating Sir Ed by 47,997 votes to 28,021.
He told Today his party knows it "made mistakes" in the election campaign, but added: "The evidence we have from around the country, particularly in the seats we were fighting, was that people were voting for the Conservatives with a washing line of clothes pegs on their nose because they were opting to stop Corbyn rather than what they also wanted to stop, which was Brexit."
Looking ahead to his party's future, Sir Ed said: "I think we need to bring liberalism to life for people, by proving, for example, our passion for social justice."
Other leadership contenders include Layla Moran, Wera Hobhouse and Christine Jardine.