A circuit court jury today convicted Kevin Cooper, a Glen Burnie carpenter, of automobile manslaughter, reckless driving, and driving while impaired by alcohol in connection with an automobile crash last Christmas Eve that killed five members of a Montgomery County family.

The eight-woman, four-man jury deliberated 5 1/2 hours before returning a verdict for which Cooper could be imprisoned for up to 15 years, two months.

The case has drawn wide attention as an example of the tragedies that can occur when a drinking person drives, and was cited earlier this year when the Maryland legislature toughened its drunken driving laws. Cooper's trial was moved to Talbot County on the Eastern Shore after Judge Donald J. Gilmore tried unsuccessfully for three days to find 12 impartial jurors in Carroll County.

Cooper, 26, who had shown little emotion throughout the 15-day trial, was composed as the jury foreman read the verdict. His wife, Roberta, stared straight ahead at the jury and never looked at her husband.

Later, Cooper's attorneys, D. Christopher Ohly and George F. Pappas, said their client would not comment on the conviction. No decision has been made on whether to appeal, they said, although they do plan to move for a new trial.

Col. Richard Proctor and his wife, Martha, who was driving the Proctor car at the time of the collision, said shortly after the accident that they had extended their "personal forgiveness" to Cooper. Today, while the jury was deliberating, they said they felt Cooper should be convicted.

"While we believe in mercy and compassion, we also believe in justice," Richard Proctor said. "Nobody wants to be responsible for sending a bright young man to jail. But there were five people whose voices could not be heard in the courtroom because they were dead. They were bright too."

Carroll County State's Attorney Thomas Hickman, the victorious prosecutor, said that an even "greater victory" resulting from the case was the impact he believes it has had on traffic fatalities in his county, which he said are down by 50 percent.

Cooper was driving his 1969 Plymouth station wagon home from a Christmas party about 3:50 p.m. when he collided with the 1981 Volkswagen Rabbit driven by Martha Proctor, who was taking her four children and three grandchildren to church in Westminster for a Christmas pageant. Proctor's two sons, aged 14 and 23, and three grandchildren, 3 years, 19 months, and 5 weeks old, were killed in the crash.

Proctor testified that she was driving 45 miles per hour on Rte. 27, near Mount Airy in Carroll County, when she looked up and saw Cooper speeding toward her in her lane. Proctor said she only had time to honk her horn and steer sharply to the left before the two vehicles collided.

Cooper told the jury he had drunk seven 12-ounce cans of beer during four hours at the party before he started the drive home. As he rounded a curve in the road, he said, the glare of the afternoon sun flashed on his windshield and he could not see the center line in the highway. He said he heard a car horn and saw a white flash and a face before losing consciousness.

He denied being drunk or feeling any effects of the alcohol. He also denied he was speeding, as government witnesses contended.

The jury did not find Cooper guilty of driving while intoxicated, one of the most hotly disputed points in the trial.

A government witness had estimated Cooper had a blood alcohol concentration above .13--the threshold of intoxication under Maryland law--at the time of the accident. But an actual test of Cooper's blood one hour and 25 minutes after the crash showed his blood alcohol level to be only .12. The official test results, not the expert's opinion, apparently carried the greatest weight in the jurors' minds.

Cooper will return to his job as a carpenter for the Welco Construction Company in Frederick, according to his attorneys. "Mr. Cooper and his wife wish simply to return to their son, Gregory, in Glen Burnie without the intense spotlight of the public media," Ohly said.

The defense attorney also said: "We have maintained throughout this trial that the state did not have the proper facts to prove the charges against Mr. Cooper. We are convinced that the state didn't meet its burden of proof. . . but obviously the jury disagreed."

Since the day of the tragedy, Cooper has been free on his personal bond, meaning his promise to appear in court when called. Judge Gilmore extended that bond yesterday until a presentence report of Cooper's background has been made. The judge said he will schedule Cooper's sentencing for November or December, depending on the court calendar.

Cooper has not driven an automobile since the accident and his Maryland driver's permit expired last February, his lawyers said. State's attorney Hickman asked the judge if he would abide by a new state law, effective July 1, requiring that a "victim impact statement" about the effects of a tragedy on its victims and their family be read before a defendant is sentenced. Judge Gilmore said he would decide that question after he has heard arguments from attorneys representing both sides.