Fonseka's Democratic Party has been registered under the Flame Torch symbol, the Elections Department said.
Fonseka, 62, said that the registering of his political party is a major step in his political ambition.
"This is the beginning of a new journey," Fonseka said.
Fonseka was running a long battle with the election officials to win recognition as several legal and administrative snags delayed his party registration.
Former elections Commissioner Dayananda Dissanayake had rejected the application filed by Fonseka to register his party.
More From This Section
He then submitted a fresh application to the current Elections commissioner Mahinda Deshapriya to register his party.
Last year two key members of his party, Tiran Alles and Arjuna Ranathunga, resigned following differences of opinion with Fonseka.
The former Army chief had previously formed the Democratic National Alliance (DNA) in coalition with the Marxist JVP or the People's Liberation Front.
He led the war against the LTTE fell off with President Mahinda Rajapaksa and challenged him in the presidential election of 2010.
Following his election defeat, Fonseka was arrested and court-martially for committing "military offences".