Michael O’Neill was so confident in his ability to turn around Bank of Hawaii when he was hired in November 2000 that he vowed to buy $10 million worth of the company’s stock.

When he stepped down as chairman and CEO less than four years later at age 57, the bank had sold or closed its mainland and international branches to refocus on Hawaii, boosted earnings to record highs and seen its stock — including the shares O’Neill purchased when he joined — increase fourfold.

Now 66, O’Neill is attempting to complete the turnaround of New York-based Citigroup. As nonexecutive chairman of the nation’s third-largest bank, O’Neill is being called the driving force behind the abrupt resignation earlier this week of CEO Vikram Pandit, who critics say wasn’t moving fast enough to cut costs in a turnaround that began five years ago.

Campbell Estate trustee David Heenan, a board member at Bank of Hawaii since 1983 and a member of the search committee that selected O’Neill in 2000, said it doesn’t surprise him that O’Neill is back in the mix again.

After O’Neill left Hawaii in 2004, saying he wanted to spend more time with his two sons on the East Coast, he ended up enrolling in a master’s program at the University of London in 2005 to study art history.

"When he left Hawaii he was economically in pretty good shape," Heenan said. "He’s had a long interest in art, particularly medieval art. It’s been an avocation, and he developed an advanced art collection when he came to Hawaii, which he expanded. It’s always been a fascination for him, and he went back to the University of London and got a master’s degree in art studies, art history or medieval art. He spent two or three years fully engaged in that effort."

In 2009, with art degree in hand, O’Neill joined the board of Citigroup in the midst of a turnaround.

"He’s an absolute turnaround champ, and all of us felt when he left here —at his age — that he had one more bullet to fire in terms of turning things around," said Heenan, a former executive for Citigroup and former dean of the University of Hawaii School of Business. "A lot of us were a bit surprised he hadn’t re-entered the working world faster than he did. Citigroup is very lucky to have him. He’s an extremely talented guy."

Current and former Bank of Hawaii executives and directors say that O’Neill, considered a hands-on chairman, has the right business acumen and leadership qualities to help new CEO Michael Corbat steer the right course for the bank.

"He is a rare combination of intellect, personality and people skill," said Peter Ho, the current chairman, president and CEO of Bank of Hawaii who oversaw commercial banking, trusts and investments during the time that O’Neill was in charge. "He had and has a real fondness for Hawaii, and, as a world-class banker, his greatest work at Bank of Hawaii revolved around recommitting the bank’s strategy to its hometown roots. His reputation coming into the organization was that of a brilliant strategist, but he is remembered best in the organization as an inspirational leader and great person to be around."

O’Neill may be best known to Hawaii residents for the "Tell Mike" television commercials, featuring O’Neill asking customers for feedback.

Bank of Hawaii was the largest bank in the state when O’Neill took over but was overtaken by First Hawaiian Bank after O’Neill began streamlining operations to raise capital and improve efficiency. International and mainland branches were either sold or closed, hundreds of employees were laid off and management was restructured.

Former First Hawaiian Chairman and CEO Walter Dods calls O’Neill an "outstanding banking executive" but said the two banks were heading in different directions at the time the two were leading their respective banks.

"He was in a turnaround situation, so he was busy cutting costs and redoing the loan portfolio so he wasn’t in the position to be head to head competing with First Hawaiian," Dods said. "He was too busy putting out the fires and restructuring the bank. It was a peacetime ‘consigliere’ versus a wartime consigliere. It wasn’t a situation where we coexisted in the marketplace, but my guess is that he would have been a tough competitor. He helped make Bank of Hawaii the solid bank it is today."

Al Landon, who succeeded O’Neill and was CEO from 2004 to 2010, said O’Neill was the point man for the strategy and overall execution of the bank’s plan to refocus on Hawaii.

"His fingerprints are all over everything," said Landon, who now lives in Park City, Utah, but still keeps busy running an investment fund for community banks and teaching part time at the University of Utah and the University of Hawaii. "Mike was the leader that put in place the strategy that made the Bank of Hawaii the effective company it is today."

Mary Bitterman, who has been on Bank of Hawaii’s board since 1984 and the lead independent director since 2000, said O’Neill stopped taking a salary in 2002 and put everything into stock because he wanted his success to be aligned with that of the bank.

"As the bank improved, obviously Mike’s financial situation improved as well," she said

Bank of Hawaii’s stock rose from a nine-year low of $11.25 a week before O’Neill took over from Larry Johnson on Dec. 3, 2000, to $47.48 on O’Neill’s final day on Aug. 31, 2004. O’Neill’s shares in the company were worth about $128 million when he left.

O’Neill said in 2004 after announcing he was leaving the bank that there were three things he’s most proud of when he looks back at his tenure.

"The financial turnaround is obviously the most visible," he said. "Two, the building up of a strong team and developing a very solid management succession plan; and three, improving the image of Bank of Hawaii with our customers, employees and the public at large."