Police plan to seal off Staples Center and allow only those with tickets into the area. Everyone else should "stay home -- stay somewhere with a television, with air conditioning, with a friend,"' McDonnell said.
Ticket winners were told to head to Dodger Stadium on Monday with a unique code and instructions to pick up tickets. A wristband will be placed on each person's wrist. Organizers will check IDs to make sure those picking up wristbands are the same people who originally applied online, said Staples Center spokesman Michael Roth.
Dodger Stadium gates were scheduled to open at about 8 a.m. Distribution was expected to end at about 6 p.m.
Fans must have both the ticket and the wristband to enter Staples Center on Tuesday. Wristbands that have been ripped, taped or tampered with will be voided.
But Roth acknowledged that high-priced scalping of the free passes was possible because winners were permitted to give anyone their second bracelet.
"Theoretically, the second wrist band can be sold," Roth said.
Police initially feared downtown would be swamped with hundreds of thousand fans. People have come from all over the world to mourn the King of Pop, assembling at his childhood home in Encino and Neverland Ranch in Santa Barbara County.
But McDonnell said he hoped people would get the message, and those without a wristband for admittance would stay clear of downtown.
More than 1.6 million people reportedly registered for tickets.
McDonnell said officers would be looking for scalpers who would try to make profit on the free tickets.
"Los Angeles is used to big events," McDonnell said, responding to a question about how the LAPD would manage the memorial. The assistant chief cited as examples the LAPD's handling of 1984 Olympics and the Lakers championship parade on July 17.
"Every agency in the city is involved," McDonnell said.
The unified command includes the California Highway Patrol and other agencies serving the greater Los Angeles metropolitan area.
Downtown hotels were quickly filling Monday.
Los Angeles city councilwoman Jan Murray said she'd "love it" if the Jacksons helped defray some of the city's expected costs associated with Tuesday's memorial, but that officials hadn't heard from the family.
Murray said the city didn't immediately have an estimate of those costs.
After a meeting Sunday, the LAPD is expected to release specifics about access gates to the secure zone for ticket holders, timing of officer deployment and other details.
Officers will be on hand Monday to help ticket-holders find their way through the crowds and get wristbands.
Parking for ticket-holders will be offered in the Staples Center and Nokia Theatre garages and plans for overflow parking will be finalized Sunday afternoon.
Businesses within the "secure zone" will be allowed to stay open Tuesday, but only ticket holders will be able to make purchases.
It was unclear if vendors would be allowed into the secure zone.
For the sake of downtown businesses in the area, McDonnell said the LAPD would try to make the day as close to the normal as possible.
No officers will be deployed in riot gear, he said, but police will be "prepared for any eventuality."
About 1,400 extra officers are expected to be deployed, but police have not disclosed the numbers or approximate cost of the operation.
McDonnell called crowd control "our responsibility," but said that "if anyone steps up who wants to defray the costs, they're welcome to do so."
The city started the fiscal year July 1, and the city budget includes money for unanticipated events such as celebrity funerals.