The abrupt resignation of Citigroup chief executive Vikram Pandit on Tuesday ended a turbulent five-year tenure in which one of the nation’s biggest banks avoided collapse with the help of a $45 billion rescue package provided by regulators, taxpayers and Congress.

Pandit, a former hedge fund executive whose own firm imploded after being acquired by Citigroup, restored the bank’s profitability, sold off assets that weren’t part of its core holdings and repaid the government loans and investments. In 2009, he accepted a salary of $1 in recognition of the bank’s reliance on taxpayer money.

But he lacked the personal and political skills to woo regulators, lawmakers or institutional investors and he left behind little affection in Washington, according to many people who interacted with him. He sometimes canceled meetings with members of Congress, was hard for government officials to reach by phone at key moments, and was often at odds with regulators, most notably Sheila Bair when she ran the Federal Deposit Insurance Corp.

Despite Citigroup’s improved earnings, Pandit also lost the confidence of big institutional investors, who voted to reject his $15 million compensation in 2011. The company declined to comment Tuesday on the details of his exit package.

Many analysts said that Michael O’Neill, a former chief executive of Bank of Hawaii who became Citi board chairman in April, believed it was time for new leadership.

O’Neill side-stepped questions about Pandit’s abrupt departure during a call with analysts Tuesday, and Pandit stressed in a statement that he left on his own accord. Still, several analysts on the call wondered why the chief executive would step down with no transition period.

The bank named Michael Corbat the new chief executive, who has been head of Citigroup’s Europe, Middle East and Africa division and who earlier at Citi Holdings sold off many of the bank’s most toxic assets to help repair its balance sheet. Corbat said in a conference call Monday that the leadership “changes do not reflect any desire to alter the direction of Citigroup, which we believe to be the right one.”

Michael Andrews, a former senior Citigroup executive based in Washington, called Corbat “a solid guy” and compared him to J.P. Morgan chief executive Jamie Dimon. Andrews said that Corbat had “an even better persona for the kind of customers you’re trying to seek.”

Some analysts, lobbyists and former Citigroup executives said that Pandit’s background in the hedge fund world was an asset in unwinding some of the complex investment vehicles and mortgage securities that helped put the bank in trouble when the economy began to collapse in late 2008.

But they said that Pandit struggled to manage such a large institution. Moreover, the bank’s deposit base did not grow and the stock price plunged to about one-tenth the level it was the day he took over.

“Citi is a lot stronger than it was. Maybe that’s faint praise, but it could have been a lot worse,” said Karen Shaw Petrou, a banking consultant in Washington. “I don’t think it’s fair to blame Pandit for the condition Citi was in in 2008. He wasn’t the CEO through the construction of the Citi edifice or excesses . . . [and] he came in right as the bubble burst.”

“He was dealt a hand and he picked up cards that were mostly twos,” she added. “It’s hard to win a game of poker that way. Could he have it played better? Obviously the board decided he could have.”

The ability of top bankers to navigate Washington is more important than ever. As one former official noted, global banks now need regulatory approval or acquiescence for stock buybacks, redemptions, mergers, divestitures and the implementation of more than 200 rules written into the financial reform commonly known as Dodd-Frank. Many details about implementation of Dodd-Frank remain under negotiation.

That focused attention on Pandit’s relationships here, and his relationship with Bair was particularly bad, former colleagues and associates said. “They really hate each other, not to put too fine a point on it,” said one person who has dealt with them both.

Bair said Pandit “had a very strong relationship with Tim Geithner and I was not somebody he wanted to deal with much. We dealt primarily with the board, not Vikram.”

She said the head of one of the nation’s largest banks never attended any meetings with the FDIC; instead, O’Neill and others gave regular reports on the bank’s progress. Bair said she suspects Pandit resented the FDIC for supporting Wells Fargo, not Citigroup, in its bid for Wachovia.

“He was quite upset when the Wachovia deal didn’t go through and that poisoned things for him. He was very bitter about it; for all I know he’s still bitter about that,” she said.

From the outset, Bair said she “never thought [Pandit] had the qualification and experience to lead an institution of the size and complexity of Citi.”

In her new book, “Bull by the Horns,” Bair says the selection of Pandit to run the storied bank reaffirmed that Citigroup had been “hijacked by an investment banking culture that made profits through high-stakes betting on the direction of the market.”

Citigroup has long been at the forefront of efforts to ease banking regulations. Its legendary chairman Walter Wriston pushed in the 1970s and 1980s to eliminate restrictions on cross-state banking and to lower capital reserve requirements, while pushing into overseas markets. In the 1990s, Sanford Weill, who sought to merge insurance, investment banking and commercial banking under the Citi umbrella, successfully lobbied to end restrictions under the Glass-Steagall legislation from 1933.

But just 10 years later, Citigroup required not only a $45 billion bailout but also a government guarantee of $301 billion on its riskiest assets. And new legislation has placed new restrictions on banks, including rules limiting the trading activities of big banks like Citigroup.