Howard K. Stern, Smith's boyfriend-lawyer, and Dr. Khristine Eroshevich, her psychiatrist, were convicted of conspiring to get the former Playboy model and reality TV star painkillers and sedatives.
Prosecutors contended during the nine-week trial that the defendants were dazzled by Smith's glamor and filled her demands for prescription drugs to protect their insider status in her personal life and her celebrity world.
Defense attorneys countered by portraying the defendants as angels of mercy who were trying to help Smith cope with her chronic pain, particularly after she gave birth to her daughter by cesarean then quickly lost her 20-year-old son, Daniel, to a drug overdose.
Smith eventually died of an accidental drug overdose in Florida in 2007, but the defendants were not charged in her death at age 39.
The jury convicted Stern of conspiring with Eroshevich to obtain drugs through the use of a false name and misrepresentation. Eroshevich also was found guilty of using a false name and misrepresentation to obtain prescriptions for the painkiller Vicodin for Smith.
Dr. Sandeep Kapoor, the physician who prescribed most of her pain medications, was acquitted of all charges in a verdict he called a triumph for the medical profession.
"This is not just a victory for me, but for patients everywhere who suffer chronic pain," an emotional Kapoor said outside court.
His lawyer Ellyn Garofalo said it also was a victory for Smith.
"The jury found she was not an addict," Garofalo said.
Stern originally faced 11 counts of conspiracy, excessive prescribing of opiates and sedatives to an addict, and fraudulently obtaining drugs by using false names but was convicted of only two conspiracy counts. The judge previously dismissed two charges against him.
As he left the courthouse, Stern told reporters, "Everything relating to the appropriateness of the medication, I was acquitted of."
His lawyer, Steve Sadow, said Stern never denied using his name on Smith's prescriptions but maintained Stern didn't know it was illegal.
Stern, 41, had been Smith's lawyer, manager, lover and friend since they met in 2001. Testimony showed they were inseparable, even when she was involved with other men.
In 2006, Smith donned a wedding gown, and she and Stern had a commitment ceremony on a catamaran off the Bahamas. They exchanged rings and vows but were never legally married.
At one point, Stern claimed he was the father of Smith's baby daughter until DNA tests made clear the father was photographer Larry Birkhead, who now has custody of the child.
Sadow contended during the trial that Smith was the love of Stern's life and he would never harm her. He also stressed that Stern was not a doctor and was relying on medical professionals to do the right thing for Smith.
Kapoor and Eroshevich also were close to Smith during her final years.
Eroshevich, 63, was Smith's neighbor and friend before treating her as a psychiatrist. Prosecutors claimed the friendship was a violation of professional ethics and called a pharmacist who testified the amount of drugs Eroshevich requested for Smith at one point would have amounted to pharmaceutical suicide.
The pharmacist refused to fill the request, and prosecutors showed Eroshevich used other pharmacies to get most of the drugs and took them to Smith in the Bahamas.
Along with conspiracy, Eroshevich was convicted of unlawfully obtaining Vicodin by fraud. The jury deadlocked on whether she unlawfully prescribed the drug.
"I feel relieved," Eroshevich said. "I'm just happy it's over."
Her attorney, Brad Brunon, said he would likely move for a new trial and might ask to have the charges against her reduced to misdemeanors.
Stern and Eroshevich remained free pending a Jan. 6 hearing when the defense can file a motion for a new trial.
If the motion is denied, the judge can sentence both defendants, but it was not immediately clear how much prison time, if any, they could face.
Kapoor, 42, who was Smith's internist, wrote numerous prescriptions for opiates and sedatives during the period he treated her. His lawyer said he followed a drug regimen originated by Smith's previous doctor who sold his practice to Kapoor.
Prosecutors Renee Rose and David Barkhurst argued that Kapoor blurred the line between patient and doctor when he was photographed kissing her at a party. They also pointed to a diary in which Kapoor discussed the "mesmerizing" experience of riding with her in a gay pride parade and wondered: "Can she ruin me?"
The jury of six women and six men spent nine weeks hearing details of Smith's troubled life and 58 hours deliberating their verdicts.
Dave Kettel, a former federal prosecutor who handled prescription drug cases and was in court for the verdicts, said the outcome might make authorities reluctant to file similar cases.
Prosecutors who handled the case said they would have no comment because the defendants still had to be sentenced.
Los Angeles County District Attorney Steve Cooley said in a written statement he was pleased there were some guilty verdicts.
"This case illustrates the problem of the overuse of prescription medicine in today's society," said Cooley, a candidate for state attorney general. "Medical professionals have a responsibility to ensure that the strict ethical guidelines of their profession are followed in prescribing medicine as part of the care of their patients."
AP Entertainment Writer Anthony McCartney contributed to this report.