Michael Vigh and Kevin Cantera were fired less than a week after Tribune editor James E. Shelledy refused their resignations.
While the reporters told Shelledy they had given the tabloid a "roadmap" of the investgation, Shelledy said he had since learned they provided a much larger part of the story.
"I feel saddened and angry that these two reporters damaged themselves, their colleagues and the reputation of the Tribune with their conduct," he said.
A message left by The Associated Press on Cantera's home was not immediately returned. Vigh's home number was disconnected when the AP called.
Shelledy had said Monday that Vigh and Cantera split $20,000 for their help on a July 2 Enquirer story headlined "Utah Cops: Secret Diary Exposes Family Sex Ring." The story has been retracted as part of a settlement between the Smart family and the tabloid.
Family spokesman Chris Thomas told CBS Radio affiliate KSL-AM's Ben Winslow the Smarts will no longer allow invasions of their privacy or attacks on their good name.
"It's not fair to Elizabeth. It's not fair for aspects of what happened to her and what she's been through to be made public," he said.
Vigh and Cantera, the lead reporters on the Smart kidnapping case, didn't tell Shelledy of their dealings with the Enquirer until last week, when they offered to resign. He refused their resignations, but put them on a year's probation and forbade them from doing any freelance work. The two also were pulled off coverage of the Smart case.
The tabloid article was published about a month after Elizabeth, now 15, was abducted at knifepoint from her bedroom. She was found March 12 in a Salt Lake suburb with two people now charged with kidnapping her.
Shelledy wrote about his reporters' involvement with the Florida-based Enquirer in his weekly column Sunday. In the column, he said Vigh and Cantera relayed rumors and "assumed the Enquirer played by mainstream rules and would consider as hearsay that which could not be confirmed, on or off the record, through police sources."
On Monday, the Enquirer sent a letter to the Tribune demanding a retraction for the column, saying Shelledy misrepresented how the tabloid got the story and wrongly implied the Tribune reporters had merely provided unsubstantiated rumors.
The tabloid's editor-in-chief, David Perel, said the Tribune reporters had told the tabloid they could vouch for the information's accuracy. He said he had a taped conversation with the reporters backing up his claim, and that the pair had "named their price" for the information.
Cantera and Vigh were quoted Tuesday by the Tribune as saying they planned to give the $20,000 to charity, even though they no longer have it in hand.
"At some point, I would like to give it to the Center for Missing (and Exploited) Children," Cantera told the newspaper. "But I haven't done that yet, so I guess it sounds pretty lame to say it."