Tweed, 53 and from Clonavon Terrace in Ballymena, was convicted over a string of child sex offences at the end of November 2012.
He had been charged with - and denied - a total of 14 offences dating from 1988. He was found guilty of 10 counts of indecent assault, two of gross indecency, and one of inciting a child to commit an act of gross indecency.
Presiding Judge Alistair Devlin described the abuse as "thoroughly despicable and deeply disturbing".
Tweed was a prominent member of the Ulster Rugby team in the 1980s and 1990s, before making his international debut with Ireland in 1995 and earning four caps.
A former DUP councillor, he later became an Independent before joining Traditional Unionist Voice. He was suspended by the party when trial proceedings got underway and has since been expelled.
In court on Friday, Judge Devlin acknowledged that a raft of character references had been supplied - including from former constituents - but he questioned whether the contributors had been made aware of the full extent of Tweed's crimes.
"He was previously highly thought of by many in society which makes the revelation of these offences all the more tragic," the judge said.
The defendant has shown, and continues to show, no remorse whatsoever in relation to any of these offences.
Judge Alistair Devlin
Prosecution barrister Richard Weir QC noted the impact of the abuse on the two victims.
"It has marred their lives and, sadly, by the look of things, it will continue to mar their lives," he told the court.
But Tweed's defence barrister Laurence McCrudden said that the victim impact assessments were untested, subjective statements - further claiming that the character references included every synonym for decency.
"These offences have cost him his liberty, his job, his position as an elected public servant and are going to weigh extremely heavy on him given the public nature of his fall from grace," he said.
Referring to Tweed's sporting and political achievements, the defence lawyer added: "There are features of this man's life which are diametrically in conflict with the evidence in this case and the conclusions of the jury."
During sentencing, Tweed stood in the dock with his hands clasped tightly in front of him.
He then blew kisses and waved to supporters in the packed public gallery as he was led away to begin his sentence.
The three-week trial in November was not the first time Tweed had been tried in relation to child sex crimes.
In 2009, he was acquitted of 10 sex abuse charges against two different young girls. At that time, it took the jury of nine women and three men just over an hour to reach their unanimous verdict.