Flowers, club scarves, football boots and banners with messages such as "Ciao Moro, you will always be in our hearts" hung on the railings outside the modern church in the Monterosso district of Bergamo where Morosini grew up.
Thousands of people applauded and touched Morosini's coffin as it was carried out of the church, draped in his number 25 red Livorno shirt. Morosini, a former Italy Under-21 international, was 25 when he died.
"This has not only hit the family but the whole community and the whole of Italy," said Bergamo resident Gianpietro Foschi.
An inquiry has been launched into whether there were delays in trying to save Morosini's life. Controversially, defibrillators were available but were not used.
Morosini's fate contrasted with the recovery of Bolton Wanderers midfielder Fabrice Muamba, who suffered a cardiac arrest during an FA Cup match in England on March 17.
Morosini's death was all the more poignant because of his tragic family life. He was providing for his severely disabled younger sister after the death of their parents and the suicide of a brother, who was also disabled.
Atalanta said they would take care of the player's sister for the rest of her life.
