Carles Puigdemont, 54, said the door had been opened to a unilateral declaration of independence.
According to Catalan officials, 90% of those who voted backed independence on October 1. The turnout was 42.3%.
Spain’s constitutional court had banned the vote and hundreds of people were injured as police used force to try to block voting.
Officers seized ballot papers and boxes at polling stations.
Spanish PM Mariano Rajoy said Catalans had been fooled into taking part in an illegal vote.
According to Catalan authorities, more than 2.2 million people were reported to have voted, out of 5.3 million registered voters. A Catalan spokesman said more than 750,000 votes could not be counted because polling stations were closed and urns were confiscated.
In a TV address, Carles Puigdemont said: “With this day of hope and suffering, the citizens of Catalonia have won the right to an independent state in the form of a republic.
“My government in the next few days will send the results of today’s vote to the Catalan parliament, where the sovereignty of our people lies, so that it can act in accordance with the law of the referendum.”
He said the EU could no longer “continue to look the other way”.
Meanwhile, PM Mariano Rajoy spoke of a “mockery” of democracy.
“At this hour I can tell you in the strongest terms what you already know and what we have seen throughout this day. There has not been a referendum on self-determination in Catalonia,” he said.
Large crowds of independence supporters gathered in the centre of the regional capital Barcelona on Sunday evening, waving flags and singing the Catalan anthem. Anti-independence protesters have also held rallies in Barcelona and other Spanish cities.
In another development, more than 40 trade unions and Catalan associations called a region-wide strike on October 3 due to “the grave violation of rights and freedoms”.
TV footage showed Spanish police kicking would-be voters and pulling women out of polling stations by their hair.
Catalan medical officials said 844 people had been hurt in clashes, including 33 police. The majority had minor injuries or had suffered from anxiety attacks.
In Girona, riot police smashed their way into a polling station where Carles Puigdemont was due to vote, and forcibly removed those inside. He voted at another station.
TV footage showed riot police using batons to beat a group of firefighters who were protecting crowds in Girona.
The national police and Guardia Civil – a military force charged with police duties – were sent into Catalonia in large numbers to prevent the vote.
The Catalan police – the Mossos d’Esquadra – have been placed under Madrid’s control, however witnesses said they showed little inclination to use force on protesters.
Barcelona Mayor Ada Colau condemned police actions against the region’s “defenseless” population, but Spain’s Deputy PM Soraya Saenz de Santamaria said police had “acted with professionalism and in a proportionate way”.
Catalan authorities said 319 of about 2,300 polling stations across the region had been closed by police while the Spanish government said 92 stations had been sealed off.
Since September 29, thousands of people have occupied schools and other buildings designated as polling stations in order to keep them open.
Many of those inside were parents and their children, who remained in the buildings after the end of lessons on September 29 and bedded down in sleeping bags on gym mats.
The anti-independence Societat Civil said there were voting irregularities, including the same people voting twice.
Catalonia is a wealthy region of 7.5 million people in north-eastern Spain and has its own language and culture.
However, Catalonia has a high degree of autonomy, but is not recognized as a separate nation under the Spanish constitution.
Image source: Wikimedia Commons President-elect Donald Trump celebrated his election victory at the Ultimate Fighting…
Millions of voters across the US chose to return Donald Trump to the White House…
Donald Trump declares victory in the US election as he addresses jubilant supporters in Florida.…
Stocks around the world are rising as Donald Trump appears to be on the cusp…
Donald Trump has won Pennsylvania, North Carolina and Georgia and taken a lead over Kamala…
Quincy Jones, the celebrated musician and producer who worked with Michael Jackson, Frank Sinatra, Ray…