Dec 28 (Reuters) - Louis Gerstner, the former CEO and chairman of IBM IBM.N, died on Saturday, aged 83.

IBM chairman and CEO Arvind Krishna announced Gerstner’s death in an email sent Sunday to employees, but did not provide a cause of death.

"Lou arrived at IBM at a moment when the company's future was genuinely uncertain. His leadership during that period reshaped the company. Not by looking backward, but by focusing relentlessly on what our clients would need next", Krishna said in his email.

Gerstner moved to IBM from being the CEO of RJR Nabisco in April 1993 after stints at American Express AXP.N and the consultancy McKinsey, becoming the first outsider to run Big Blue, as IBM was called.

During the nine years he led the computer giant, he was widely credited with turning around a company that was facing potential bankruptcy, pivoting the company to business services. He radically changed IBM's culture and focus while slashing expenses, selling assets and repurchasing stock.

Gerstner retired as CEO of IBM in 2002, with the stock some 800% higher than when he had started, moving to become the chairman of Carlyle Group until his retirement in 2008.

The author of "Who Says Elephants Can't Dance" and co-author of "Reinventing Education: Entrepreneurship in America's Public Schools," Gerstner was on the board of several companies including Bristol-Myers, the New York Times NYT.N, American Express, AT&T and Caterpillar CAT.N.

Gerstner was passionate about public education in the U.S, launching an initiative at IBM to use company technology in schools.

He established the Gerstner Philanthropies in 1989, which included the Gerstner Family Foundation, emphasizing support for biomedical research, environmental and education initiatives, and social services serving New York City, Boston, and Palm Beach County, Florida.