Ronald Seymour, a retired businessman of Hendon Lane, Finchley, had also pleaded guilty at a previous hearing to possession of a prohibited weapon and possession of ammunition.
He was remanded in custody to be sentenced on 27 October at Southwark Crown Court.
DI Sally Jeffrey of Trident Non-fatal Shootings Team said:
"The relationship between Seymour and his wife had broken down over a period of time causing much animosity between them and, as a result of his actions, leaving Mrs Delvaille ultimately fighting for her life. The Metropolitan Police Service is determined to bring perpetrators’ of domestic violence to justice and deal with the victims’ and their families sensitively."
The court heard that police were called at approximately 17:20hrs on Thursday, 11 February 2010 to reports of a woman shot in Cavendish Avenue N3.
The woman, Sonia Delvaille, a former croupier aged 65, was taken by ambulance to a west London hospital suffering gunshot wounds to her face which resulted in two of the bullets becoming lodged in her skull. The injuries have caused long term, life-changing affects.
Witnesses described how Ms Delvaille and a man had been seen arguing prior to the incident and he had dragged her down the street whilst she was screaming. He then appeared to fire a hand gun from inside a white plastic bag, and as she fell to the floor he fired a further two shots at her before running away.
An hour later police received a call from a solicitors firm known to Ronald Seymour, stating that he had rang them and told them he had shot his wife and he was sat on a wall outside.
Armed police attended the address and arrested him in the street.
During his arrest Ronald Seymour made many admissions to officers that he had shot his wife and directed them to where he had disposed of the gun, which was then recovered from a stream in Waverley Grove.
Prior to the shooting it is known that Sonia had attended an appointment with her solicitor earlier that day regarding obtaining a financial settlement following their recent separation.
When interviewed by police Seymour gave no comment and was charged on 12 February as above and remanded in custody.