The troubled former star appeared at Waverley Local Court on Friday, when he pleaded guilty to driving while under the influence of methamphetamine.
The charge was the latest in a growing list of drug- and domestic violence-related offences.
The 53-year-old tested positive for methamphetamine after being pulled over for random testing about 11.30am on July 28 at Bellevue Hill, in eastern Sydney.
O'Keefe's lawyer Jahan Kalantar told the court the TV personality had been in rehabilitation and was co-operating with court orders.
"We accept he has a poor traffic history and has struggled with addictive substances," he said.
"He's taken rehab very seriously."
O'Keefe had been out of the country and returned to Australia for his plea and sentencing.
Magistrate Michael Barko fined him $404 and suspended his licence for six months.
The same court was told in October that O'Keefe would make a genuine attempt to turn his life around if given the opportunity to enter drug rehabilitation rather than face jail time.
He pleaded guilty on that occasion to drug possession, trespassing and breaching a court order, with prosecutors agreeing to withdraw an additional charge of intimidation.
At the time, Magistrate Jacqueline Milledge told O'Keefe if he continued to offend the court may come to the view he was unable to be rehabilitated.
"Your life has just completely gone off the rails," she told O'Keefe.
"The only person that's going to make your life any different is going to be you."
Mr Kalantar previously said O'Keefe was at a crossroads and risked becoming institutionalised if he continued down the wrong path.
The ex-host was on bail in September when he experienced a near-fatal heroin overdose.
He was subsequently arrested and his grey Mercedes was searched, resulting in the discovery of a "clear crystal substance" when he reported to Rose Bay police station.
O'Keefe was a Seven presenter for more than 15 years, most notably hosting game show Deal or No Deal and breakfast program Weekend Sunrise.
He was convicted of domestic violence offences in January and had an appeal on those charges dismissed earlier in September.
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