Making his first conference speech since being ousted as leader, Charles Kennedy pledged his loyalty to his successor Sir Menzies Campbell, and betrayed no bitterness over his removal.
He received two standing ovations as he insisted he wanted to remain in the political front line.
Mr Kennedy warned the party not to play down its pro-European credentials, lose sight of the case for a fairer voting system, or underestimate the importance of the environmental agenda.
Delegates in the packed hall stood and cheered as he took to the stage at Brighton and gave him further rapturous applause at the end of his 35-minute unscripted speech.
Mr Kennedy, who was forced to resign in January after admitting a drink problem, said that the year had been the "best of times and the worst of times". He said he had received "innumerable media opportunities" to talk about his downfall but had turned them all down.
Watched by Sir Menzies, Mr Kennedy recalled that during the leadership contest he had promised his loyalty to whoever succeeded him as leader. He added: "Ming Campbell knows that has been the case and you should know that is going to remain the case."
Mr Kennedy said he was optimistic about the party's prospects, contrasting the fall in Labour and Tory support since 1997 with the advance in backing for the Liberal Democrats. He said: "Politics is where I want to be and it's our politics I want to stay in."
He urged activists not to hold back on championing their principles, even when they were "unfashionable". He singled out Britain's place in Europe, arguing it could be as crucial for defining the party as was its opposition to the Iraq war three years ago.
He said the party had to keep the "flame alive" for decentralising power to the regions, and said a new directly elected second chamber should be given a more meritocratic name than the House of Lords.
Nor should the party ease off from highlighting global warming, Mr Kennedy said. Referring to an earlier vote in favour of new green taxes, he said: "Today was a good start but, my God, for all our futures, there is so much more to be done."
Mr Kennedy added: "For each and every one of us as British Liberal Democrats, the best is yet to come."
Within minutes of leaving the stage, bookmakers installed him as favourite to be the next party leader. It was his only appearance in Brighton, but he will be a guest tomorrow on BBC1's Question Time. The last time he was on the programme, he conspicuously failed to rule out ever standing again for the party leadership.
Sir Menzies hailed his predecessor's speech as "outstanding" and said: "He is a very accomplished speaker; you could see by the way he was received that there's great affection for him in the party."Reuse content