"The country needs you!" the former president had told Hillary Clinton, urging her to run this year, according to accounts of the conversation included in Edward Klein's new biography of Obama.
Obama, Bill Clinton had said, according to book excerpts, "doesn't know how to be president" and is "incompetent."
The title of Klein's explosive, unauthorised biography of Obama, "The Amateur", was taken directly from Bill Clinton's bombshell criticism of the president, the author said.
"Barack Obama," Bill Clinton said, "is an amateur."
The withering criticism is incredible, given the fact that Bill Clinton is actively campaigning for Obama's re-election, the New York Post reported.
According to the book, Bill Clinton unloaded on Obama and pressed Hillary to run against her boss during a gathering in the ex-president's home office in Chappaqua last August that included longtime friends.
"The economy's a mess, it's dead flat. America has lost its Triple-A rating . . . You know better than Obama does," Bill had said.
Hillary resisted the entreaties, according to two of the guests interviewed for the book.
"Why risk everything now?" a sceptical Hillary told her husband, emphasising that she wanted to leave a legacy as secretary of state.
"I want my term (at the State Department) to be an important one, and running away from it now would leave it as a footnote," Hillary had argued. She said she had the option of running again in 2016.
The book's explosive claims were shot down by spokesmen for the White House and the Clintons, who closed ranks.
Bill Clinton's spokesman Matt McKenna said the excerpts were "totally and completely false" and called Klein "a known liar." Phillipe Reines, a spokesman for the secretary of state, noted that Hillary Clinton challenged the veracity of an earlier book Klein wrote about her, "Truth About Hillary."
White House spokesman Eric Schultz accused Klein of making up facts to sell books.
"Nobody in their right mind would believe the nonsense in this one, especially since both Secretary Clinton and President Clinton have been loyal and supportive of the president (Obama) at every turn," he said.
