There were fears that nobody would turn up, or, worse, that the fractures caused by the movement's decision to abandon Silvio Berlusconi's government in December would degenerate into a brawl. Against the odds, though, the party came out not quite kicking, but still very much alive.
An unusually gentle Umberto Bossi, the League's mercurial leader, kept the hooligan element at the congress on a tight leash while laying down a clear vision of the future: a future firmly rooted in the political centre, in which the League's commitment to a "federalist" decentralisation of Italy would take precedence over high-risk games-playing with Mr Berlusconi or anyone else.
"To say that we have to join up with monopolistic political parties or else die is idiotic," Mr Bossi told an adoring crowd of around 5,000 hard- core supporters. "We need to return to the long march towards federalism, cauterise our wounds and go back on to the offensive."
He admitted many mistakes, including his dictatorial leadership tendencies, and announced a new, more democratic internal structure. Every time the crowd starting chanting "Bossi, Bossi", he signalled to them to shout "Lega, Lega" instead to detract attention from himself.
He said he would return to the grass roots to campaign for greater autonomy in the regions and work to extend his federalist movement towards the centre and south of Italy. The message was more serious than anything the abrasive Mr Bossi has said for months.
Although he could not resist calling Mr Berlusconi an anti-democratic Frankenstein, he kept his habitual stream of insults to a minimum. "Tomorrow we will identify the traitors and sell-outs and call them by their name," he said. "But not today. Today we need to listen and understand."
Mr Bossi won overwhelming endorsement from what remains of his party and seemed to pull off a genuine political coup, looking for once like a serious politician while still appealing to the boisterous lower-middle- class football fans at the core of his support.
It did not all go his way, though, and at first the congress looked in serious danger of falling apart. One of the League's senators, Erminio Boso, suddenly withdrew his promise to publish a damning document about Mr Berlusconi's business practices, saying he needed more time.
Even Mr Bossi did not turn up for his opening-day address, putting his supporters in a foul mood as they chased one dissident speaker off the platform.
But the tone improved markedly as the weekend progressed. By the time Mr Bossi's right-hand man and former interior minister, Roberto Maroni, announced he was quitting, the impact of this most high-profile of defections had been fully absorbed and the audience was as good-humoured as lambs.
Even revitalised, the League still needs to find an electorate and a political role. For years Mr Bossi thrived as the bogeyman of the old system, breaking the rules of political etiquette with his unkempt hair, scruffy clothes and outrageous slogan ce l'ho duro - "I've got a hard- on."
Having rejected Mr Berlusconi and the right in clamorous fashion - partly because the strictures of power were too much for such a maverick movement - the League now has to make its home elsewhere. But there may be nowhere to go, since the centre-left is polarising behind Romano Prodi, a Christian Democrat economist and does not appear to have space to give the League a leading role.
Mr Bossi will have to hope that he can compete with and perhaps displace Mr Prodi. But even his supporters are not sure he can do it.
"It's not by shouting `Bossi, Bossi' that we can win elections," said a delegate, Umberto Tarterini. We need new people and new ideas. We'll have to see if we can find them."