Gary Mayor Eddie Melton said Jackson became a friend and called him often to ask what he could do to support the city.
"Tito would come when there were no cameras, when there were no press conferences, concerts," Milton said.
Jackson died at the age of 70. A family spokesperson said he suffered a fatal heart attack Sunday while driving to his home in Oklahoma.
The loss is a huge blow to fans who stopped by the Jackson family home to pay their respects.
Patsy Brown brought her friend, visiting from California, and shared a toast to Jackson.
"I personally have never, ever, ever driven by this house, and I've lived here my whole life. And it took something like this, sadly," Brown said.
Demont Pinder had already planned to make a pilgrimage to the Jackson family home, but when the artist learned of Jackson's passing, he packed his art supplies.
"My way of paying homage and a tribute is a blank canvas and doing a portrait," Pinder said.
Pinder painted a portrait of a teenage Tito, hoping to share it with his family.
"You're looking at a family that inspired the whole world, the whole globe. It's amazing," Pinder said.
Jackson, the guitarist of the group, learned to play the instrument from his father, Joe Jackson.
He released a solo album and continued to perform with his brothers, speaking several years ago about the loss of his younger brother, Michael.
"Every show we feel his presence on stage. He helps us through and helps us with what we're doing," Jackson said, at the time.
Jackson was last in Gary a couple of months ago, performing at the Hard Rock Casino, and according to Gary's mayor, he was planning to visit the city next week.