Edward Hedley was found at his home in Newcastle in December 2012 in an emaciated state and suffering from extreme pressure sores. He later died.
His son, William Hedley, denied neglect but was found guilty on 2 February, after a trial at Newcastle Crown Court.
The 64-year-old was jailed for 18 months.
The trial heard police were called to the pair's home in Royal Crescent by the ambulance service on Christmas Eve 2012, after William Hedley became obstructive and would not allow his father to be taken to hospital.
Once Edward Hedley arrived in hospital his frail condition led to police being called.
Following his death on 12 January 2013 a post-mortem examination found he had died as a result of neglect.
William Hedley was convicted of being a carer who ill treated/willfully neglected a person without capacity.
Following sentencing, Det Ch Insp Jackie Coleman, of Northumbria Police, said: "There had been numerous attempts from Newcastle Council to provide assistance for Edward Hedley over a sustained period of time, but his son had stubbornly resisted all attempts, despite the best efforts of the local authority.
"It is difficult to believe that in this day and age that an elderly person, supposedly under the care of his family, could have died because they had been so neglected.
"It is sad to say that is what has happened in this most unusual case."
A son who resisted attempts by a council to help his 91-year-old father, who then died as a result of his neglect, has been jailed.