He was sent to prison on November 2 after the High Court found him to be in contempt. Miss Justice Elizabeth Dunne told Quinn that his contempt was so serious that she could come to no other conclusion that it mandated a term of imprisonment.
She could not ignore the extent and degree of contempt by Quinn and imposed a nine-week jail term.
Today, a spokesperson for Sean Quinn support group Concerned Irish Citizens said: "Concerned Irish Citizens would like to welcome home Sean Quinn from Mountjoy, and hope that 2013 will be the year that the people of Ireland obtain answers to questions.
"The most vulnerable people in our society have no choice about austerity and brutal cuts so the least that they deserve is the truth, nothing more, nothing less."
Quinn's contempt related to allegations of a plan to put his family's €500m property empire beyond the reach of the former Anglo Irish Bank.
Fallen tycoon Quinn was granted temporary release from prison on Christmas Eve when the former billionaire was collected from the Dublin jail by his son, Sean Jnr, and driven home in an Audi A5 car.
His temporary release allowed him to spend Christmas Day at his palatial mansion in Ballyconnell, Co Cavan. He was also able to attend the Christening of his granddaughter Orna.