Police Scotland has confirmed the decision was made to reinstate Constable George Park, 46. However, the move has caused unease among some colleagues in the force, which has run a zero tolerance campaign against domestic violence.
Park, who has 17 years' service with the former Strathclyde force, spent 10 months in custody awaiting trial following two attacks on his wife Frances at their home in Ayr and another at his parents' home in the town in 2009.
Sheriff Jack McGowan imposed an 18-month sentence at Ayr Sheriff Court, but Park walked free because he had been remanded for over 10 months. The sheriff also imposed an indefinite non-harassment order forbidding him from having any contact with his 44-year-old wife.
Park, who had latterly worked at Glasgow Sheriff Court, was then on sickness leave from his £36,000 a year job. He was finally sacked in December 2011 after failing to turn up at a disciplinary hearing.
However, Park lodged an appeal and continued to earn a wage. Since he carried out the assaults in July and August 2009 his wages have cost the public purse more than £140,000.
A Police Scotland spokeswoman said: "PC Park was reinstated following an appeal, although he remains suspended on full pay, and as of today is still a police officer."
The reinstatement decision was taken in February, but has only just been revealed.
Police Scotland said the decision was made after an appeal before the office of the Chief Constable of the former Strathclyde force, which was replaced by Police Scotland in April.
Park was convicted of seizing his wife by the body at their home on July 19, 2009, and repeatedly punching her on the head to her injury.
He was also found guilty of repeatedly punching her on the head and body two days later, knocking her to the ground and threatening her with further violence.
Park was convicted of carrying out a third assault on his wife at his parent's address on August 4, 2009, during which he seized her by the hair and attempted to strike her on the body to her injury.
Sheriff McGowan concluded Park had displayed such "a course of conduct" that only a custodial sentence was appropriate.
During the trial Mrs Park said she was left black and blue after the attacks in her home and, fearing for her safety, went to stay with her in-laws in Ayr.
She said: "I knew I had to leave, or I would be dead."
That did not deter Park. Referring to the assault she suffered in the kitchen at her in-laws, Mrs Park said: "He was holding on to my head and wouldn't let go. The pain was incredible."
A social inquiry report described Park as "a potentially dangerous individual".
His colleagues are astounded that he has been allowed back on the force. One police source said: "It is incredible that at a time when we are banging the drum about 'zero tolerance' towards domestic violence, someone like Park has been taken back as a police officer.
"In any other walk of public life once he was convicted of such serious offences, he would have been out the door and that would have been an end to it.
"People have every right to accuse Police Scotland of having double standards."
Mrs Park was not available for comment, but a friend said the victim was shocked at the decision.
Angela Devine, manager of Glasgow Women's Aid, said: "It would be a concern if this man had been through the court and judicial system, then is free to be a police officer who will come into contact with victims of domestic abuse."