Charles Kennedy won two standing ovations from Lib Dem activists as he returned to the political frontline at the party's conference in Brighton.
Mr Kennedy looked confident and relaxed as he spoke without notes in his first big speech since admitting a drink problem and quitting as party leader.
He said "the best is yet to come" for the party and insisted it could be a force for change in British politics.
This year had seen the "best of times and the worst of times", he said.
Farewell or return?
Mr Kennedy received a rapturous reception in the conference hall, although several delegates thought he was not ready to return to the front bench yet, despite giving a strong performance.
Sir Menzies Campbell, Mr Kennedy's successor as leader, hailed the speech as "outstanding".
"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," said Sir Menzies.
Former leader Lord Ashdown said: "I thought it was a farewell speech from a politician who is leaving the scene.
"Charles will now have to decide how to re-enter politics at some point in the future."
But Baroness Williams, former leader of the party in the Lords, said she thought the "opposite" to Lord Ashdown.
"I thought it was a speech saying I am dedicated to the cause. I am not coming back right away but I still want to be involved," she said.
"I just thought what an extraordinarily gifted man and what a great pity it was that he fell prey to this illness, alcoholism."
Lady Williams said it was "unlikely but not impossible" that Mr Kennedy would become Lib Dem leader again at some point in the future.
Mr Kennedy said he had passed up numerous chances to talk to the media about events because he wanted to speak to the Lib Dem conference first.
"Politics is where I want to be and it's our politics I want to stay in," he told delegates.
There have been reports that Mr Kennedy might plan a return to being leader but Mr Kennedy said he had kept to his promise to stay loyal to the new leader.
"Ming Campbell knows that has been the case and you should know that is going to remain the case," he said.
But, although Sir Menzies led the standing ovation, there was no handshake for the cameras between the two men.
Mr Kennedy thanked his supporters, saying he felt "personally and politically optimistic".
He said the Lib Dems had the momentum in British politics since 1997 while Labour and the Conservatives had lost votes.
"We are a force for change in British politics," he said.
"But we can change the circumstances and the context for the better around about us without, in any sense whatsoever, surrendering that we are Liberal Democrats, we are staying Liberal Democrats and my God we are proud to be Liberal Democrats."
He reminded delegates he had taken them to the Lib Dem's biggest number of MPs for 80 years at the last election.
And he argued the party could now seek "outright victory" in next year's Scottish Parliament polls.
Mr Kennedy said his opposition to the Iraq war had been vindicated and claimed the conflict had damaged the integrity and reputation of British diplomats.
"It's absolutely damnable," he said.
The Ross, Skye and Lochaber MP said he wanted to see more progress on social justice, House of Lords reform and fighting global warming.
And he urged delegates: "Let's get more pro-European, please."