A New York judge yesterday awarded $1 million in damages to a man wrongfully imprisoned for 24 years, but noted that he accepted testimony about the man's mental health "cum grano salis" with a grain of salt .

Isidore Zimmerman, 66, who was sentenced to death for murder in 1938 but fought a protracted battle for his release and later for $10 million in compensation, said he was disappointed with the judgment.

"All along I fought for my day in court, and when I finally got it, it wasn't what I thought it would be," said Zimmerman after the judgment was announced. "I am disappointed, and if I had an income I would appeal. But I don't, and so I will now begin to support my lovely wife in a manner to which she has never really become accustomed."

The award, made by Judge Joseph Modugno of the Court of Claims after two weeks of expert testimony about Zimmerman's mental anguish, health problems and loss of potential income, ties the record for prisoner compensation. A California man was awarded $1 million in 1980 after spending two years in prison on a murder charge.

The award is tax free. After Zimmerman pays his law firm, Shea and Gould, a one-third contingency fee and about $40,000 in costs, he will be left with about $630,000.

A passionate man who was once famous as a jailhouse lawyer at Dannemora Prison in New York, Zimmerman gained celebrity again yesterday. He held a press conference attended by 14 television crews and was scheduled to be a guest on ABC's "Nightline" last night and "CBS Morning News" today. Paramount pictures is considering filming the story of Zimmerman's life, and he has been offered $60,000 for a television biography, with Judd Hirsch playing the part of Zimmerman.

Since his release from prison in 1962, when an appeals court judge found that an overzealous prosecutor had suppressed evidence in his behalf, the Zimmerman claim has been a mirror reflecting issues of state liability, capital punishment, constitutional law and the ebb and flow of New York state politics.

More than half Modugno's 10-page judgment discussed why the case had come to his bench in the first place, leaving as his only function "to establish the quantum of judgment for the defendant."

Modugno stated that he accepted psychiatric reports about Zimmerman's suffering--including one doctor's belief that his prison experience was analogous to that of inmates at Auschwitz--with a grain of salt.

Modugno pointed out that legislation permitting Zimmerman to sue for damages had been vetoed three times by Gov. Nelson Rockefeller, and included in his judgment former New York attorney general Louis Lefkowitz's statement in 1969 that "if this bill were approved the result would be to establish a precedent broadening the state's moral obligation to a point beyond reason."

The judge said the New York legislature, in passing a bill permitting Zimmerman to sue for damages, which was signed by Gov. Hugh Carey, had "resorted to every device known in the use of the English language to commit the state as far as was legally possible to liability."

He concluded that "it is not for this court to question the judgment of a previous court, or of Gov. Carey (despite the fact that Gov. Rockefeller vetoed the same bill three times) or of Attorney General Robert Abrams (whose predecessor thrice recommended dismissing) or the enabling legislation which permitted claimant to sue."

Zimmerman said yesterday, of Modugno, that "this man was prejudiced against me from the start. He ruled against me at every turn. I didn't get my fair day in court."

Fred Fabricant, Zimmerman's lawyer, noted that Modugno had been appointed by Rockefeller, and was a former colleague of Lefkowitz.

Zimmerman was arrested when he was 21 and charged, as one of five "East Side Boys," with the murder of a police detective. Three of the five went to the electric chair, but Zimmerman's sentence was commuted to life two hours before he was scheduled for execution. He spent the next 23 years in New York prisons, where he was repeatedly punished as an incorrigible. Upon his release he held a variety of jobs, his last as a doorman working midnight to 8 a.m. When he retired on disability last year, his salary was about $210 a week.

Zimmerman said he had asked for a very large sum of money to fund the Fannie and Morris Zimmerman Foundation, named after his parents, to investigate miscarriages of justice. He also planned to buy a Cadillac with "six doors."

"With this amount I can't have the foundation I wanted," he said yesterday. "I can't even afford the car. I don't feel at all like a lottery winner. Besides, after all this time, there's still the feeling that somehow they'll pull the rug out from under."

Zimmerman conceded, however, that he was suffering from "anticlimax," and that it is true he is now a millionaire--at least before deductions--and that he is planning a party this weekend, and that the Fannie and Morris Zimmerman Foundation is not, as yet, a lost cause.

"I'm looking for a grant," Zimmerman said. "Don't you think I could get a grant?"