Carles Puigdemont, who is in self-imposed exile in Belgium, still faces charges of disobedience and embezzlement, which could land him eight years in prison.
Spain dropped sedition charges against the leader of Catalonia's failed bid for independence on Thursday, following a legal reform.
The Spanish Supreme Court said it would no longer pursue charges against Carles Puigdemont for inciting people to rebel against Spain's central government.
Catalonia is a wealthy region in northeastern Spain, which has long sought independence.
In 2017, Puigdemont led a controversial independence referendum that was banned by central authorities and met with a heavy police crackdown.
It led to a constitutional crisis.
Puigdemont, who is currently in self-imposed exile in Belgium, still faces charges of disobedience and embezzlement in Spain, which could land him with a jail term of up to eight years.
Sedition carried a maximum jail term of 15 years under Spanish law. But the crime was abolished, after a reform to Spain's legal code.
Spain has repeatedly tried to get Puigdemont extradited during his stays in Germany, Belgium and Italy, though they have failed each time.
On Thursday, Spanish Supreme Court judge Pablo Llarena said he would submit a new extradition request to Belgian authorities so that the Catalan leader can be tried in Spain for lesser charges.
But whether this will happen depends on rulings by EU courts, which need to decide if Puigdemont has immunity and if multiple extraditions can be requested.
Puigdemont's lawyer, Gonzalo Boye, said Llarena had a "fundamental rights and political persecution problem".
Spain amended its penal code late last year to remove the historic sedition law, which took effect on Thursday.
The Supreme Court also dropped sedition charges against other Catalan exiled separatist politicians Antonio Comin, Lluis Puig, Clara Ponsati and Marta Rovira.
All the exiled Catalan leaders fled Spain in 2017 after the botched attempt to break away from Spain.
Prime Minister Pedro Sanchez, who has pardoned those convicted over the events, said the move should reduce political conflict between Madrid and Catalonia.
Opposition parties said it was designed to assure Sanchez's socialist-led coalition of the continued support of independence parties in contentious parliamentary votes.