Gbagbo, who was freed conditionally by the ICC after he was cleared in 2019 of crimes against humanity, had been barred by the country's electoral commission from running.
"We have just submitted the candidacy file of our political leader, president Laurent Gbagbo, the father of democracy in Ivory Coast who we have applied to be our candidate for the presidential election," said Georges-Armand Ouegnin, president of the pro-Gbagbo coalition called Together for Democracy and Sovereignty (EDS).
The October 31 election in the world's top cocoa grower is set to be tense after years of political turbulence and civil war, and Gbagbo's return to national politics is highly sensitive.
The country remains scarred by a conflict that erupted after the 2010 vote when Gbagbo refused to hand over power to the victor, current President Alassane Ouattara. Around 3,000 people lost their lives in several months of violence.
Gbagbo, who has not made any public statement about whether he wishes to run again, is living in Brussels pending the outcome of an appeal against the ICC ruling.
In the meantime, he can travel, provided the country of destination accepts him.
Struck from electoral lists
Independent Electoral Commission chief Ibrahime Coulibaly-Kuibiert has said that anyone convicted of a crime would be struck from the electoral lists for the ballot.
Gbagbo, 75, was sentenced in absentia to a 20-year term last November for the looting of the local branch of the Central Bank of West African States during the post-election crisis.
In theory he could be jailed if he were to set foot in Ivory Coast, which makes any return a hot-button issue in the election run-up.
Ouegnin said the decision to block Gbagbo from running was political, while judicial sources said they believe his candidacy is unlikely to be validated.
"The Constitutional Council will have the heavy responsibility before the Ivorian people and history to decide on the validity" of blocking him from the electoral roll, said Ouegnin.
He called for the release of all political prisoners and the return of political exiles including Gbagbo.
The 2020 election is already set to be tense.
Violence erupted after Ouattara's announcement he is seeking a third term, claiming the lives of at least eight people in August.
The constitution limits presidents to two terms, but Ouattara and his supporters argue that a 2016 constitutional tweak reset the clock.
Candidates have until midnight Monday to submit their files with the electoral commission.
Relatives of the former rebel leader Guillaume Soro, forced into self-imposed exile in France in the face of a long list of legal problems at home, are expected to submit his candidacy on Monday.
Former president Henri Konan Bedie, 86, who also contested the 2010 election, is also expected to run.