Gladys Knight performed the hymn "Our Father" (The Lord's Prayer) and moved many to tears, according to one guest who asked not to be identified because of the sensitivity of the day.
When it was over, many of the the 200 mourners hugged each other. Among them were Elizabeth Taylor, Jackson's ex-wife Lisa Marie Presley, Barry Bonds and Macaulay Culkin.
The Rev. Al Sharpton, who gave a eulogy at the public event and at Thursday's service, also extolled Knight's earlier performance of "His Eye is on the Sparrow."
"Gladys Knight sang her heart out. Now we prepare to lay him to rest," Sharpton posted on his Twitter account during the service that was held outside and then within the marble mausoleum.
The mourners followed the crowned, lushly flower-draped casket as Jackson's five brothers - each wearing a bright red tie and a single crystal-studded glove - carried it into the mausoleum. The 11-year-old Paris cried as the group entered the imposing building and was comforted by her aunt, LaToya.
Paris and brothers Prince Michael, 12, and Prince Michael II, 7, known as Blanket, began the service by placing the crown on their father's golden casket. They were composed through most of the hour-and-a-half ceremony.
As it ended, Katherine Jackson appeared extremely weary and had to be helped to her car, according to the guest. Earlier, she had a difficult time going into the mausoleum; she was overcome, turned back, and it wasn't clear if she went in at all, the guest said.
The Jackson family's tardy arrival delayed the service for nearly two hours; no explanation was given to mourners. The invitation notice indicated the service would begin promptly at 7 p.m.; it began closer to 8:30.
The 77-year-old Taylor and others were left waiting in the late summer heat, with the temperature stuck at 90 degrees just before sunset, and some mourners fanned themselves with programs for the service. As darkness fell, police escorted the family's motorcade of 31 cars, including Rolls-Royces and Cadillacs, from their compound in Encino to Forest Lawn, about a 20-minute journey, with the hearse bearing Jackson's body at the end.
About 250 seats were arranged for mourners over artificial turf laid roadside at the mausoleum, and a vivid orange moon, a mark of the devastating wildfire about 10 miles distant, hung over the cemetery.
There were two oversized portraits of a youthful, vibrant Jackson mounted next to the casket amid displays of white lilies and roses. At Jackson's lavish public memorial, red roses covered his casket.
A large, blimp-like inflated light, the type used in film and television production, and a boom camera hovered over the seating area placed in front of the elaborate marble mausoleum. The equipment raised the possibility that the footage would be used for the Jackson concert documentary "This Is It," or perhaps the Jackson brothers' upcoming reality show.
More than 400 media credentials were issued to reporters and film crews who remained at a distance from the service and behind barricades. The few clusters of fans who gathered around the secure perimeter that encircled the cemetery entrance struggled to see.
Maria Martinez, 25, a fan from Riverside, Calif., who was joined by a dozen other Jackson admirers at a gas station near the security perimeter, gave a handful of pink flowers she had picked at a nearby park to a man with an invitation driving into the funeral.
"Can you please put these flowers on his grave?" she told him. "They were small and ugly, but I did that with my heart. I'm not going to be able to get close, so this is as close as I could get to him."
The man consented, adding, "God bless."
Glendale police said all went smoothly and there were no arrests.
Jackson will share eternity at Forest Lawn with the likes of Clark Gable, Jean Harlow and W.C. Fields, entombed alongside them in the mausoleum that will be all but off-limits to adoring fans who might otherwise turn the pop star's grave into a shrine.
The closest the public will be able to get to Jackson's vault is a portion of the mausoleum that displays "The Last Supper Window," a life-size stained-glass re-creation of Leonardo da Vinci's masterpiece. Several 10-minute presentations about the window are held regularly 365 days a year, but most of the building is restricted.
The Jackson family had booked an Italian restaurant in Pasadena for a gathering Thursday night, and family members and guests were seen coming and going late into the night.
"I feel like I watched Michael finally given some peace and I made a commitment to make sure his legacy and what he stood for lives on," Sharpton said outside the restaurant around midnight. "So at one level we're relieved; another level we're obligated."
The ceremony ends months of speculation that the singer's body would be buried at Neverland Ranch, in part to make the property a Graceland-style attraction. An amended copy of Jackson's death certificate was filed Thursday in Los Angeles County to reflect Forest Lawn as his final resting place.
In court on Wednesday, it was disclosed that 12 burial spaces were being purchased by Jackson's estate at Forest Lawn Glendale, about eight miles north of downtown Los Angeles, but no details were offered on how they would be used.
The King of Pop died a drug-induced death June 25 at age 50 as he was about to embark on a comeback attempt. The coroner's office has labeled the death a homicide, and Jackson's death certificate lists "injection by another" as the cause.
Dr. Conrad Murray, Jackson's personal physician, told detectives he gave the singer a series of sedatives and the powerful anesthetic propofol to help him sleep. But prosecutors are still investigating, and no charges have been filed.
AP writers Derrik J. Lang, Anthony McCartney, Sue Manning, Sandy Cohen and Ryan Pearson and APTV reporter John Mone contributed to this report.