Skakel was convicted in June of beating Martha Moxley to death in 1975, when they were 15-year-old neighbors in Greenwich. He was sentenced last month to 20 years to life in prison.
The appeal cited 26 issues, plus a catch-all 27th issue that left open the door for additional arguments. It did not appear to raise any arguments that had not been put forth earlier, most of which were rejected by the trial judge.
Among other things, the defense lawyers argue that prosecutors failed to notify them of information that could have helped the defense; that the case should have been dismissed because of the statute of limitations; and that the case should not have been transferred to adult court from juvenile court, where Skakel was first charged, because of his age at the time of the murder.
The appeal argues that the 1975 sentencing laws violate the state Constitution by giving the Board of Parole the power to determine how long Skakel will be imprisoned. It also questioned whether a sentence of 20 years to life which the appeal said "means a life sentence" was cruel and unusual punishment for a crime committed by a minor.
The state Supreme Court refused last year to rule on the issue of transferring the case from juvenile court to adult court, saying it could not act until a verdict had been reached.
Defense lawyers also objected to the prosecution's closing argument, which included a multimedia presentation combining Skakel's own words with pictures of the crime scene, and to the judge's instructions to the jury.
Skakel is being held at Garner Correctional Institution in Newtown.
His lawyers last week challenged a decision denying him bail while the case was appealed, saying a 1998 law that bars bail to convicted murderers is unconstitutional. They also argued that Skakel, the father of a 3-year-son, is not a flight risk, saying he could live at his home in Windham, N.Y., with an electronic monitoring device.
Martha Moxley's battered body was discovered on Oct. 31, 1975, under a tree on her family's estate in the gated Greenwich community of Belle Haven. She had been bludgeoned with a golf club later traced to a set owned by Skakel's mother — and stabbed in the neck with the shaft of the club.
At trial, prosecution witnesses said Skakel was romantically interested in Moxley, but suggested he was upset because his older brother, Thomas, an early suspect in the slaying, was making advances on his attractive blonde neighbor.
The case went unsolved, creating speculation that wealth, privilege and the Kennedy connection had protected the Skakel family. Meanwhile, Benedict said Thursday, Skakel "thumbed his nose at this family of grieving neighbors."
Attention turned to Michael in the early 1990s, when he gave new details of his activities the night of the murder to a private investigator hired by the Skakel family. Books about the case were written by Dominick Dunne, former Los Angeles police Detective Mark Fuhrman, and journalist Tim Dumas.
Skakel was arrested in 2000 after an investigation by a one-judge grand jury. He declared his innocence and fought to have the case heard in juvenile court, only to have a judge rule the state had no juvenile facility in which to lock up a middle-aged man.
Prosecutors had no eyewitnesses and little forensic evidence. Instead they presented about a dozen people who said they had heard Skakel confess or make incriminating statements, starting the day Martha's body was found. Among them were a Skakel family chauffeur and former classmates of Skakel at a substance abuse treatment center in Maine.
One witness, Gregory Coleman, was dead of heroin use by the time Skakel's trial began. But prosecutors were permitted to read Coleman's pretrial testimony into the record, including an allegation that Skakel once told him: "I'm going to get away with murder, because I'm a Kennedy."