Bernard Ryan was caught by a police sniffer dog at Cairnryan ferry port near Stranraer in June last year.
The load of herbal cannabis had been hidden under the trailer of Ryan's Ford Transit recovery vehicle.
Ryan, 61, had decided to copy the same technique to store the drugs that landed him with a prison sentence in Ireland in 2005.
Ryan, now of Manchester, insisted during the latest trial that he had no knowledge of the drugs.
The new conviction came following a two-day trial at the High Court in Glasgow.
Jailing Ryan judge Sean Murphy QC told him: "You have been convicted of smuggling a very large amount of cannabis from the UK mainland to Ireland.
"You are getting a bit old for this sort of thing."
Officers from the Border Policing Command swooped at Lochryan Port, Cairnryan, on June 19 last year while Ryan was waiting to board a ferry to Northern Ireland.
Police dog Buster sniffed something suspicious coming from Ryan's vehicle during a routine check.
It was also discovered the underside of the Ford pick-up had been modified which one officer described as "very unusual".
It soon lead to a huge amount of cannabis being uncovered - believed to be one of the largest seizures ever made at the busy port.
Jurors were shown photos of a large number of heavily wrapped packages that were stored in compartments under plywood and metal in a bid to avoid detection.