The 5-foot-3-long male struggled initially with his captors, but then gave up, officials said.
"I think he was tired too," Robb said. "Wherever he came from, or however he got here, he a very healthy animal."
Robb said the hook he uses doesn't penetrate a gator's thick skin very deeply, just long enough for captors to get close.
"Just grabbed hold of him and then we tied him up and taped him up and that was an afternoon," Robb said. "The second I put my hands on him, the hook fell out. Hence people ask, 'How do you catch an alligator?' 'Just barely' is the answer."
Robb showed off the seemingly relaxed, captured gator — with heavy-duty black tape around its mouth, and a red-and-black plaid bow-tie leash — to reporters and onlookers.
The east side of the lagoon was fenced off from the public on Sunday night as part of the Chance search.
Public interest in the animal probably frightened Chance and sent it into hiding, officials said.
Chicago Animal Care and Control Executive Director Kelley Gandurski on Tuesday renewed earlier promises that Chance would not be killed after capture.
The animal will end up at a zoo or a sanctuary so it'll have "the best chance at a good life, a most natural life," Grandurski said.