The 31-year-old stunned the Magpies in January when he said he wanted to quit St James' Park and return to Argentina for personal reasons.
Buenos Aires-based San Lorenzo, with whom Coloccini enjoyed a season-long loan spell in 2001, held talks with Newcastle but were unable to conclude a deal.
After lengthy discussions with Toon boss Alan Pardew, Coloccini made an about-turn and opted to stay in the north east until at least the end of the season.
Coloccini then confirmed earlier this summer that he wanted to stay at Newcastle after all, much to the delight of the Toon faithful.
Speaking ahead of his side's Premier League opener with Manchester City on Monday evening, Coloccini revealed that his relationship with the supporters played a key role in his decision to stay.
"My dream is to play at the top level of football. My family could understand that and that's why I'm here now," he said.
"My relationship with Newcastle and with the fans was very important in helping me to make my decision.
"I've supported San Lorenzo since I was small, but I feel something for Newcastle now."
The news is almost certain to disappoint San Lorenzo's most famous supporter, Buenos Aires-born Pope Francis.
Coloccini revealed he had spoken with the pontiff while on international duty with Argentina, but even he was unable to persuade the defender to quit the Premier League.
"It's well known that Pope Francis is a big San Lorenzo fan. He has a season ticket and everything," he added.
"You could tell he still really loves the club when he spoke with us all in the Argentina squad. He spoke about the club a lot."