Carlson is now 44. He was 16 at the time of the killing and attended Foothill High School with the girl.
Her body was discovered the afternoon of April 5, 1984, not far from Interstate 680. She had been stabbed numerous times.
Carlson, who is being held at the county jail without bail, is scheduled to return to court April 30 for a pretrial hearing.
Wearing a red jail uniform, he smiled and laughed as he chatted with his attorney, Cameron Bowman, before his brief hearing Monday. Bowman was hired by Carlson's family to take the case over from Richard Foxall, the public defender originally assigned the case.
Carlson has served time, including on a felony count of lewd or lascivious act with a child under 14 years of age, and he is on the state's Megan's Law list of sex offenders. Police have said Faelz did not appear to have been sexually molested.
He could have been prosecuted as a juvenile because he was under 18 when Faelz was murdered, but Alameda County Superior Court Judge Rhonda Burgess ruled in January that Carlson should be prosecuted as an adult.
She cited the degree of criminal sophistication exhibited in the killing, the severity of the crime, and previous failed attempts at rehabilitating Carlson, among other considerations.
When Carlson was arrested and charged last August, Pleasanton police said that after Faelz's body was discovered, they conducted exhaustive crime-scene processing and interviewed classmates, friends, school faculty and nearby residents.
Faelz was last seen alive about an hour before her body was found. The freshman girl often took the bus home from school but had recently started walking home to avoid being teased by other students riding the bus, her mother, Shirley Orosco, said in a 2008 interview with the Pleasanton Weekly.
Like many of her classmates, Faelz took a back route from the high school, walking on a path that connected through Aster Court to Lemonwood Way and under I-680 to her home in the Valley Trails neighborhood. That day, she only made it part way when police believe she was approached and subsequently stabbed to death.
Fellow high school students who walked the same path found Faelz's body at about 3:25 p.m., only 10 to 15 minutes after investigators believe she was killed, Lt. Darrin Davis said in a 2008 interview. Police also received a call from a trucker who reported seeing her body from the freeway just minutes before the students discovered her.
The crime remained unsolved for 27 years until Pleasanton police announced Aug. 7 that DNA evidence had linked Carlson to Faelz's death.
Police said that in the many years since the murder, they kept the case open and investigated any tips or new information that emerged.
In late 2007, police again re-examined the evidence that was collected at the time of the killing, using scientific analyses that weren't available in 1984. Evidence was submitted to two different laboratories for examination.
In October 2010, the FBI crime lab in Quantico, Va., provided information to Pleasanton police that led them to Carlson as a suspect.