The 90 days stems from the 30 days possible for each of Lohan's original infractions: her two DUIs and a count of reckless driving.
The judge also ordered Lohan to complete a 90-day inpatient substance abuse program after she's out of jail. She must refrain from drinking alcohol and submit to random drug-testing, plus her probation has been kicked up a notch to "formal probation" and she has two days to report for duty.
Lohan burst into tears upon hearing her fate, as did sister Ali sitting toward the back of the courtoom.
She was ordered to report to the courthouse by July 20 at 8:30 a.m. to begin serving her term at the Century Regional Detention Facility in Lynwood. She will also be required to wear her SCRAM bracelet until then.
"Nowhere did I say substantial compliance would be good enough," added Revel. "Because had I known then [that Lindsay was not in compliance], we would've had this hearing a lot sooner."
Revel noted that Lindsay's had a history of noncompliance and "ongoing excuses."
"She had to go once a week," the judge said. "I ordered her to do it and I couldn't be more clear and it wasn't done."
Lohan's attorney, Shawn Chapman Holley, told the court in closing arguments that the thespian believed she was living up to the terms of her probation and that Right On, the program she was enrolled in, had given her the go-ahead to miss various sessions as long as she made them up.
"We've acknowledged the violation. We've always acknowledged the violation," the legal eagle said, noting that officials at Right On, the program Lohan's enrolled in, allowed her absences of up to 21 days.
"It's evident that she has taken the [program] seriously as she's going to be finished with the program by the end of this week," added Holley. "It's clear she's made a significant change and is doing well. She completed the program except for three AA meetings."
Throwing herself on the mercy of the court, Lohan herself tearfully addressed the judge directly before sentencing.
"I just wanted to take a minute to say that as far as I know I was being in compliance with my program. When I asked to leave town, they would give me permission to leave town. I wasn't expecting any special treatment aside from the understanding that I have to provide for myself, I have to work," said Lohan.
After acknowledging that Right On allowed her time off for various jobs, she choked up as she explained she did her best to balance her career and her probation obligations.
"I'm not taking this as a joke. It's my life and career. I've learned from my experiences, I take responsibility for my actions," added Lindsay, bursting into tears. "Honestly, it did wake me up. Yes, of course it scared me. Also it confused me because I thought it was OK to miss those classes. Had I known...I would've made sure I was in town each week.
"It's just been such a long haul and I don't want you to think I don't respect you on your terms because I really did think I was doing what I was supposed to do," she said in conclusion.
Deputy District Attorney Danette Meyers wasn't buying the contrition act.
"You have not caught her attention. When the defendant was ordered to be here in [May], she was in France and didn't come back to this court," said the prosecutor. "I would ask the court to have her continue to wear the [SCRAM] device until she's compliant."
Neither did the judge.
"She knew it, so the court doesn't buy that at this time," Revel said.
Holley noted that Lohan is due to finish her original alcohol-education program by July 16.
Meanwhile, even if Lohan ends up serving only about 25 percent of her sentence, due to L.A. County protocol concerning nonviolent female offenders charged with misdemeanors, it'll be some major time served compared with the 84 minutes she spent locked up in 2007.
(Originally published July 6, 2010 at 3:35 p.m. PT)
—Reporting by Claudia Rosenbaum