Mel Miller, who rose to the highest ranks of New York State government as speaker of the State Assembly and publicly feuded with Gov. Mario M. Cuomo, but who was forced from office because of a fraud conviction that was later overturned, died on Friday in Manhattan. He was 79.

His wife, Elizabeth Miller, said the cause was complications of lung cancer.

Mr. Miller was found guilty in 1991 of defrauding clients of his private law practice in the 1980s, when he was an Assembly member from Brooklyn but before becoming speaker of the Democratic-controlled body.

An appeals court threw out the conviction in 1993, saying his actions had not constituted felonies. But Mr. Miller, who had been in the Assembly for 21 years and speaker for five, said he would not resume his political career.

“I don’t think elective office is for me,” he said. “Maybe it’s a little ego. You were king in your own domain; it’s hard to come back into the system as something else.”