NEW YORK, NOV. 14 -- Former stock speculator John A. Mulheren Jr. was sentenced today to one year and one day in prison and fined $1.68 million for manipulating stock in a scheme with convicted trader Ivan F. Boesky.

Mulheren, a flamboyant and successful stock trader who was convicted in a trial that featured Boesky's first public testimony in Wall Street's insider trading scandals, was freed pending appeal of the charges.

Mulheren was the only person implicated by Boesky to go to trial rather than strike a plea agreement.

A jury in July found Mulheren, 41, guilty of helping Boesky drive up the price of Gulf & Western Inc. stock in 1985. He faced a maximum of 20 years in prison at sentencing before U.S. District Judge Miriam Goldman Cedarbaum.

Prosecutors had charged that Mulheren bought 75,000 Gulf & Western shares at Boesky's behest, driving the stock to $45 a share, the price at which Boesky wanted to sell about 3.5 million shares back to the company.

Boesky agreed in November 1986 to plead guilty to one count of lying to federal investigators and pay $100 million in fines. He was released from federal custody in April after serving two years of a three-year term.

Boesky was called as a witness against Mulheren, his former business associate and friend. Boesky admitted in testimony that he traded suitcases stuffed with cash for confidential information about imminent takeovers.

Mulheren flouted convention in court as he had in his Wall Street career. During testimony, he wore a tennis shirt, blue jeans and boat shoes.

In 1988, after learning that Boesky had implicated him, Mulheren was arrested at his Rumson, N.J., mansion carrying a loaded assault rifle. Police said he planned to shoot Boesky. New Jersey officials later dropped weapons-possession charges against Mulheren. Mulheren's lawyers blamed the incident on his failure to take lithium prescribed to treat manic depression.

Some criminal charges against Mulheren remain because the jury was unable to reach a verdict on 26 additional counts of securities fraud, mail fraud and record-keeping violations.