Jackson, 26, was found not guilty of sexual and assault and rape.
After an eight-week trial that the judge said had been made extremely hard for the jury by intense media coverage, the men walked free but remain suspended from playing until the Irish rugby union completes its own review.
The defence argued that the woman made false rape allegations because she regretted having group sex with the men and feared it may have been documented and would appear on social media. All four defendants in the case were unanimously cleared of their charges, in the case involving Jackson, Stuart Olding, Blane McIlroy and Rory Harrison.
"A dedicated and specialised team of police officers and staff from the Rape Crime Unit, led by Detective Chief Inspector Zoe McKee, all worked diligently on this case".
The woman testified that she had gone to a nightclub in Belfast before going back to a party at Jackson's home.
Jackson's solicitor Joe McVeigh hit out at the investigation, saying: "It's our belief that the investigation has been characterised by the turning of a blind eye to inadequacies in the evidence of the complainant combined with the very apparent investigative bias".
Brendan Kelly QC, who defended Jackson in court, told jurors his client had character references that described him as "placid" and a "likeable lad with no self importance".
She was one of several women who had come to his house after meeting the men in a Belfast nightclub a day after they had returned from Ireland's tour of South Africa, he told the court.
Out of respect for my employers I have nothing further to comment.
Echoing numerous sentiments shared in an earlier statement by his teammate and similarly cleared Paddy Jackson, Olding suggested that he was "sorry for the hurt that was caused to the complainant".
They said: "We wish to acknowledge that this has undoubtedly been a hard and extremely traumatic time for all involved".
The Irish Rugby Football Union and Ulster Rugby said officials will review the matter, in line with existing procedures for all contracted players.
It also noted differences between the court system in Ireland and in Northern Ireland.