Edward Chernoff also said Dr. Conrad Murray never prescribed or gave Jackson the drugs Demerol or OxyContin. He denied reports suggesting Murray gave Jackson drugs that contributed to his death.
Chernoff told the AP that Murray was at the pop icon's rented mansion on Thursday afternoon when he discovered Jackson in bed and not breathing. The doctor immediately began administering CPR, Chernoff said.
"He just happened to find him in his bed, and he wasn't breathing," the lawyer said. "Mr. Jackson was still warm and had a pulse."
Jackson's family requested a private autopsy in part because of questions about Murray, the Rev. Jesse Jackson said Saturday. Murray also told the family an autopsy should be performed, Chernoff said.
Three days after the death of the King of Pop, celebrities descended on Los Angeles for a spectacular celebration of Jackson's life at the annual BET awards show.
Joe Jackson, Michael's father, walked on the red carpet wearing a black hat, sunglasses and a dark suit. He planned make an onstage appearance, show publicist Bobbi Marcus said.
"I just wish he could be here to celebrate himself," he said. "Sadly, he's not here, so I'm here to celebrate for him."
In a statement read at the show, Jackson's parents said they solely had the personal and legal "authority for our son and his children." It was their strongest declaration yet about their son's affairs.
People close to Michael Jackson have said since his death that they were concerned about his use of painkillers. Los Angeles County medical examiners completed their autopsy Friday and said Jackson had taken unspecified prescription medication.
Chernoff said any drugs the doctor gave Jackson were prescribed in response to a specific complaint from the entertainer.
"Dr. Murray has never prescribed nor administered Demerol to Michael Jackson," Chernoff said. "Not ever. Not that day. ... Not Oxycontin (either) for that matter."
Paramedics were called to the mansion while the doctor was performing cardiopulmonary resuscitation (CPR), according to a recording of the emergency call.
Because Jackson was so frail, Murray "administered with his hand behind his back to provide the necessary support," Chernoff said. Some have speculated the doctor botched the CPR.
"He's a trained doctor," Chernoff said. "He knows how to administer CPR."
Medics spent three-quarters of an hour trying to revive Jackson. He was pronounced dead later at University of California Los Angeles Medical Center.
Murray was interviewed by investigators for three hours Saturday. His spokeswoman called Murray "a witness to this tragedy," not a suspect in the death, and police described the doctor as cooperative.
The attorney said Murray will wait to speak publicly until after the police and forensics investigation is complete.
"One of his best friends just died, essentially in his arms - yeah he's looking forward to telling his story," Chernoff said.
Chernoff also said the promoter of Jackson's 50-show London concerts, AEG Live, owes the cardiologist $300,000.
"His contract with the promoters states he would receive an amount of money each month to be his (Jackson's) personal physician and they have failed to honor that contract," Chernoff said. "They are two months behind."
Randy Phillips, president and CEO of AEG Live, acknowledged the contract called for Murray to be paid $150,000 a month, but said the contract required Jackson's signature.
"Michael never signed the contract," Phillips said.
He also said the doctor's claim for payment may be against Jackson's estate, not AEG which was merely advancing the money to Jackson.
A private pathologist hired by the Jackson family completed a second, private autopsy Saturday, the Los Angeles Times reported, citing unnamed people familiar with the case.
A second autopsy can allow the family to get some information about a death almost immediately, including signs of heart, brain or lung disease or fresh needle punctures, said Dr. Michael Baden, a medical examiner not involved in the Jackson case.
"Usually if it looks normal with the naked eye, it looks normal under the microscope," said Baden, who recently performed a second autopsy on actor David Carradine.
Los Angeles County coroner's officials said their autopsy found no indication of trauma or foul play. But because of additional tests, an official cause of death could take weeks to determine.
There was no word from the Jackson family on funeral plans. Many of Jackson's relatives have gathered at the family's Encino compound, caring there for Jackson's three children.
Al Sharpton, who arrived in Los Angeles on Sunday afternoon, said he was heading to the Jackson compound and would talk with the family about how to memorialize the late pop star. Sharpton said they want to hold memorials in key cities around the globe and also planned a memorial service Tuesday at the Apollo Theater in New York.
It also wasn't clear what would become of Jackson's Neverland Ranch. Investor Thomas Barrack previously set up the joint venture with Michael Jackson after the singer nearly lost the ranch to foreclosure.
Barrack feels close to family members and wants to hear their thoughts on how best to honor Jackson's memory, said Owen Blicksilver, a spokesman for Colony Capital LLC, the Los Angeles-based firm where Barrack is chairman and CEO. The investor joined Jackson's brother Jackie, Jermaine and Tito for lunch Saturday at the sprawling Santa Barbara County property.
A White House adviser said on NBC's "Meet the Press" that President Barack Obama had written to the Jackson family to express his condolences.