Skakel, 41, who once reportedly boasted he'd get away with murder because he was "a Kennedy," was convicted in June of murdering Martha Moxley in 1975 when they were 15-year-old neighbors in Greenwich, Conn.
Judge John F. Kavanewsky decided to put off sentencing after rejecting defense motions for a new trial and hearing victim impact statements at a packed hearing in Norwalk Superior Court.
"I think he should spend the rest of his life in jail," the dead girl's mother, Dorthy Moxley, 70, said, urging the judge to sentence Skakel to the maximum sentence of 25 years to life.
"I spent almost 27 years of hell and anguish trying to live...a normal life," she said, her voice quavering throughout her statement.
"The tears that filled my eyes when I thought of Martha's death were the worst," she said. "I couldn't stand the thought of her suffering."
The victim's brother, John Skakel, said in his statement, "I have never seen my mother in so much pain" in the years immediately following the murder.
"My mother cried all the time for a while, and the intensity of her emotions was frightening to me," he said. He also called for the maximum sentence.
Dorthy Moxley blamed the Skakel family for delaying the investigation and making it "almost impossible."
Skakel sat impassively during the statements, but was seen crying as he talked to family members during a recess.
Despite a much-touted link to the Kennedy family, no Kennedys showed up at the hearing. Skakel is a nephew of Ethel Skakel Kennedy and the late Sen. Robert F. Kennedy.
Kavanewsky said he would sentence Skakel on Thursday after statements from attorneys for both sides.
The defense had argued that Skakel should get a new trial because, among other things, the prosecution withheld a police sketch of a person seen in the neighborhood about the time Moxley was slain.
The defense claimed the sketch resembled Kenneth Littleton, an early suspect in the case, and that jurors might have come up with a different verdict if they had been shown the sketch.
Littleton had just started working as a tutor in the Skakel home the day before Moxley was killed the night before Halloween 1975. Investigators subsequently dismissed Littleton as a suspect.
Prosecutors argued they had not withheld the sketch, and that the defense knew about it but never requested it. The state said the sketch actually resembled another resident of the neighborhood and was of no real importance.
The judge has a wide range of possible sentences under guidelines that were in effect in 1975. The minimum sentence would be 10 to 25 years, which means that Skakel could get out of prison after serving only six years.
If the judge goes for the maximum sentence, Skakel could be sentenced to from 25 years to life. With credit for good time and time served, he could be released in about 13 years.
Because he was just 15 at the time of the slaying, Skakel likely would have escaped any jail time if convicted as a juvenile. However, his case was moved up to superior court where he became subject to tougher sentences.
The judge received more than 160 pages of letters urging leniency in sentencing Skakel.
Skakel's defense attorneys, Hope Seeley and Hubert Santos, argued for a light sentence, saying his life over the past 20 years made it "clear that Mr. Skakel poses no threat to society."
Skakel was convicted June 7 of beating and stabbing Moxley to death with his late mother's golf club Oct. 30, 1975. At the time they both lived in the fashionable Belle Haven section of Greenwich, Conn.
The defense motion said Skakel's father, industrialist Rushton Sr., was an alcoholic who often beat Skakel. The motion traced Skakel's life through the death of his mother, Anne, who died of brain cancer in 1972.
The motion also detailed the abuse Skakel endured at the Elan school for troubled youth in Maine.
"No greater punishment could be imposed upon Mr. Skakel than the beatings and abuse he endured while at Elan," the motion said.
It was there that Skakel reportedly told a fellow student that he would "get away with murder" because he was "a Kennedy."
Among those writing to support Skakel was his cousin, Robert F. Kennedy Jr., an environmental lawyer.
"The portrait of Michael painted at trial and by his detractors in the national press could not be farther from the truth," Kennedy wrote. "Michael is a kind and gentle man, utterly unspoiled and hardworking."
"During his short life, Michael has endured unusual suffering," Kennedy wrote. "He was a small, sensitive child -- the runt of the litter, with a harsh and occasionally violent alcoholic father who both ignored and abused him."
Kennedy said that while Skakel had flaws, "his flaws are the thin vapor that obscures a tower of virtues."
Regardless of whatever sentence is imposed, Skakel's defense was expected to continue appeals, a prospect that prompted Dorthy Moxley to comment, "I think I am going to have Michael Skakel as an appendage for the rest of my life."
Skakel is divorced from his wife, Margot, but they have joint custody of their son, George, who turns 4 in December.
(Reported in Boston by Dave Haskell)