The Mean Girls star faced 240 days behind bars amid charges she lied to police following a California car crash last year, accusations which also put her at risk of breaking the terms of her probation for a 2011 jewellery theft conviction.
Trial proceedings against the embattled actress were expected to kick off on Monday morning, but the hearing was pushed back after Lohan turned up at the Los Angeles courthouse 48 minutes late following a series of flight dramas.
Her late arrival allowed her lawyer Mark Heller extra time to negotiate with prosecutors and by the time the case went before Judge James R. Dabney, the two parties had reached an agreement on a plea deal.
Lohan agreed to serve a 90-day sentence in a treatment facility, complete 30 days of community service in her native New York, and undergo 18 months of psychotherapy, which she has already enrolled in. She was also ordered to pay fines and restitution to the other driver involved in the crash last summer.
In exchange for jail alternative, Lohan pleaded no contest to lying to cops and reckless driving. The latter charge also carried a mandatory five days in jail, although prosecutors allowed the actress to include that in her rehab stay and she will therefore not spend any time behind bars.
She also admitted to violating her probation and was given a 180-day jail sentence, which was suspended providing she completes her rehab and community service with no further drama. As part of the deal, Lohan must stay away from drugs and submit to random testing.
Despite her late arrival, all the drama of Lohan's morning in court took place outside - she was dowsed with what looked like gold dust as she made her way from a car to the entrance and then her estranged father heckled her attorney Mark Heller as he attempted to address the media after the proceedings had ended.
Reality TV star Michael Lohan accused the lawyer of using his daughter for publicity, and berated him throughout his courthouse steps press conference, as Heller attempted to explain why he and his client had agreed to accept a plea deal they had previously turned down.
Michael Lohan yelled: "Why are you up still there?"
Once Heller, who was drafted in to replace the actress' longterm lawyer Shawn Holley last month, left, Lohan staged his own press conference, accusing the attorney of "trying to cash in on my daughter's notoriety for his own professional interests".