Anthony Paton, 56, was behind the wheel of a Commodore one afternoon in July, 2009, when his car smashed into an oncoming Toyota Yaris on Gundaroo Drive.

Paton's son, Andrew John Paton, 29, of Ngunnawal, died in the crash, while a front passenger also sustained serious injuries.

The father was drunk, recording a blood alcohol level of .281.

His licence had expired, and the car was unregistered at the time of the crash.

Paton had been drinking with his son and two others that morning.

During his trial, the court heard that Paton was driving erratically, speeding and trying to slide around corners, just before he collided with the oncoming car.

The court heard on Monday that Paton has had problems with alcohol for 40 years.

The author of a pre-sentence report on the offender told the court that Paton had been overly optimistic about his ability to overcome his drinking problem.

The author said Paton had told her "it would just work out all right, they can test me every day".

She said such optimism was not realistic, given Paton's history.

A University of Canberra psychology professor later told the court that Paton was well suited for long term residential rehabilitation, and said he had been diagnosed with an alcohol disorder, post-traumatic stress disorder, and major depressive disorder, all of which required treatment.

Justice Hilary Penfold sentenced Paton to a total of five years in prison for culpable driving causing death and culpable driving causing grievous bodily harm.

He has already served time in custody, meaning that prison sentence would start on July 25, 2013.

Paton will be eligible for parole on April 24, 2016.

He has also been disqualified from driving until further order of the court.