In interviews with The Inquirer, ethics experts questioned that plan, saying that the senior Fattah would almost certainly learn donors' names anyway. They said full disclosure was the better policy.
After the newspaper raised the issue with the congressman, the fund reversed course.
In a statement Friday, the fund's single trustee, George R. Burrell, a top lieutenant in the John F. Street mayoralty, pledged that all donors and their gifts would be made public.
Rep. Fattah did not respond to a request for an interview but issued a statement Friday saying he supported full disclosure. He also said:
"I appreciate the efforts of those who have stepped forward to help my son Chip in his struggle to pay the substantial legal fees. . . . I love my son and believe in his innocence."
The federal investigation of the younger Fattah became public in February 2012, when FBI and IRS agents carted off boxes of records and computer equipment from his office and apartment in the Residences at the Ritz-Carlton, across from City Hall.
The probe is reportedly focusing on issues involving bank loans he received as well as questions about his tax returns.
Fattah Jr. could not be reached for comment. He has said he did nothing wrong.
Gregory P. Miller, one of his criminal-defense lawyers, said Fattah Jr. had been cooperating with the investigation for more than a year. Miller said defense attorneys also had met three times with federal officials to provide information.
In interviews, experts on ethical issues said the legal defense fund raised potential issues.
"There is a question of whether or not people would be contributing to Chaka Fattah's son's defense fund to curry favor with his father," said Melanie Sloan, executive director of Citizens for Responsibility and Ethics in Washington.
Rendell said the plan had been to make sure that Rep. Fattah never saw the list of donors.
Rendell and Goode said, however, that they did not oppose full disclosure of the donors. Rendell said any such disclosure would first have to receive legal approval.
Craig Holman, a lobbyist with Public Citizen, a nonprofit organization that advocates for more transparency in Washington, said the Fattah Jr. fund could be a magnet for "businesses and special interest groups who have a lot of money and who are looking at ways to throw more money at the feet of the congressman by any means possible."
Holman said any plan short of full disclosure would have had problems. Even if a donor list had been kept from Rep. Fattah, Holman said, he would likely learn the donors anyway. "You can bet the lobbyist for the [donating] company is going to let the congressman know about it," Holman said.
Under congressional rules, legal defense funds that benefit officials must disclose donations, and the size of donations is capped. Those rules apply to funds for the officials, not their relatives.
On Friday, Burrell said all donations, amounts of donations, and all fund expenditures would be made public "to be fully transparent."
Rendell said Friday that he did not know why the fund had shifted its policy but that he supported full disclosure. "That's fine with me," he said.
Interviewed separately, Rendell and Goode praised the younger Fattah and said they had known him for years.
"He's a wonderful kid," Rendell said. "I'm not doing it because he is Chaka Fattah's son, though I have a good relationship with Chaka. I'm doing it because I have a good relationship with him."
Said Goode: "I have known Chip since he was born. He is in essence one of my children. . . . He's a friend. And he's a friend who needs some help."
Rendell said he would give $1,000 to the fund. He said the goal was to raise $100,000 or $150,000.
In a fund-raising pitch letter signed by Rendell and Goode, donors were instructed to send their checks to the Center City apartment of Fran Fattah, Chip Fattah's sister and a lawyer. She did not respond to a request for comment.
Rendell said the letter was sent last month to 200 to 300 recipients, mainly people who knew the younger Fattah or who had made campaign donations to his father.
"Although the Fattah family has already contributed hundreds of thousands of dollars for expenses unrelated to legal fees, additional financial help nonetheless is needed to ensure that Chip has legal representation going forward," the two Democrats wrote.
Fattah's congressional office did not respond to an e-mail from The Inquirer asking it to explain the phrase "expenses unrelated to legal fees."
Rendell said he could not explain it.
As a U.S. representative, Fattah, a Democrat, is paid $174,000 a year. His wife, NBC10 anchor Renee Chenault-Fattah, is paid a substantial salary. The station would not provide the amount.
The younger Fattah, who attended university but did not graduate, has run a consulting business and operated a concierge firm catering to the wealthy, such as by chartering them private jets on short notice.
He has also worked as a subcontractor with a businessman operating a network of schools for students with disciplinary problems.
In 2011, Fattah Jr. said on a credit application that he made $300,000 a year.
He has run into financial difficulties in recent years, facing lawsuits for $16,000 in unpaid gambling debts and delinquencies on a series of loans.
Contact Craig R. McCoy
at 215-854-4821 or email@example.com or follow @CraigRMcCoy on Twitter.
Inquirer staff writer Martha Woodall contributed to this article.