Patrick Cullen pounced on a 24-year-old woman in a secluded lane in Milngavie, East Dunbartonshire, in February 2011.
The married 44-year-old remained at large despite a media appeal to catch the attacker.
But, in late 2012, a relative of Cullen appeared on the national DNA database - and through that the cabbie was traced.
It helped police link the dad-of-two to DNA found at the scene at the time.
Cullen today returned to the High Court in Glasgow after earlier being convicted of the indecent assault. His lawyer said Cullen maintained he was "not a sex offender".
But, Lord Matthews said the assault was "serious" adding: "The aggravating feature was that you were a taxi driver - your job was to take the woman home."
A smiling Cullen gave a thumbs-up to his wife in court as he was lead handcuffed to the cells.
He was also placed on the sex offenders register for the next 10 years.
A jury last month heard how Cullen picked up his victim in the city's Glassford Street in the early hours of February 19, 2011 after she had been at a gay bar.
Soon into the journey, creepy Cullen - who claimed his name was Gary - quizzed her on her sexuality and asking "rude questions".
Cullen, of Moodiesburn, North Lanarkshire, drove his private hire Chrysler into a quiet area in Finlay Rise in Milngavie - near to Rangers Murray Park training ground - before halting the vehicle.
Recalling her ordeal, the woman - who is a lesbian - said: "He told me to get into the back of the car. I was scared, but I did it."
Cullen then indecently assaulted his victim and made her perform a sex act on him while ignoring her loud sobs.
She only escaped his clutches when he dropped her home - but the brazen sex attacker still demanded she fork out the £7 fare.
The victim called police and a hunt began to catch Cullen.
DNA was found near the scene and the woman was also able to help construct an e-fit of her attacker - which bore a striking resemblance to Cullen.
But, detectives had no joy until more than 18 months after the attack.
A relative of Cullen had a DNA check around that time - although it is not known why.
It is thought the DNA had similarities to that discovered at the scene before police were pointed in the direction of Cullen.
Cullen insisted during the trial that the woman agreed to what happened in his car and that she "enjoyed" it.
Cullen also claimed - despite media appeals and the e-fit - that he had never been asked about the incident until police came to his door in September 2012.
Geoffrey Forbes, defending, today said Cullen had the support of his wife and his family despite the conviction.
Mr Forbes added: "He maintains that he is not a sex offender."