The TV star was given a ten week prison sentence, suspended for 18 months, after pleading guilty to a single charge of harassment when he appeared for trial at Huntingdon Magistrates’ Court in Cambridgeshire.
They Think It’s All Over star McGrath, 60, whose wife Nicola was in court to support him, harassing his victim, who cannot be named for legal reasons between May 2015 and August 2016.
McGrath, who also appeared in comedy documentary Three Men In A Boat, originally denied a stalking charge but admitted harassment when the charge was changed.
The court heard how McGrath sent the woman electronic messages, approached her in the street and followed her.
The 60-year-old, of Grantchester Street, Cambridge, also sent letters to the woman’s husband.
As well as the suspended sentence, he was given a five-year restraining order banning him from contacting his victim, her three children, her husband or her current partner.
He was also ordered to pay £200 costs.
In 2013, McGrath was cautioned by police over a drunken assault against a couple.
He was said to have attacked the man and a woman, who were trying to help him while he was “heavily in drink”, police said at the time of the incident.
The man suffered a bloody nose and a scratched face, and McGrath was subsequently arrested over the assaults, which took place at a house in Pool, near Redruth in Cornwall, where McGrath grew up.