"People have come from all over Aceh. They are happy to be here just to see [di Tiro] for that split minute. His heart has always been in Aceh," Bakhtiar Abdullah, former GAM negotiator who was jailed by the Indonesians, said.
"There are people who were very loyal to him who would die for him, and they have never seen him before. They are still loyal to him and they would do anything for him," Abdullah said.
Al Jazeera's Step Vaessen, reporting from Banda Aceh, the regional capital, said that thousands of people had gathered to welcome Di Tiro.
"They have been crying for their leader, it's an amazing sight ... I have never seen so many people gathered here ... they are so happy," she said.
"Di Tiro said he is on a social visit, but the government is nervous about his return. However, he is 83-years-old, he's a Swedish national, and I am not sure if he wants to permanently live here."
Aceh rebels gave up their arms and separatist rebellion in 2005 under a power-sharing agreement with the Indonesian government.
Di Tiro's declaration of independence from Indonesia in 1976 sparked the 30-year civil war.
His's return comes a day after the man who helped broker the peace deal - Martti Ahtirsaari - won the Nobel Peace Prize.
Di Tiro has been living in Sweden since late 1970's.