The 26-year-old will not appeal against the punishment, which has been backdated to September 2017, when he tested positive for cocaine.
The decision means Hardaker will be free to join a new club in November.
Hardaker's representatives Chadwick Lawrence Solicitors said in a statement: "Following a one-day hearing in front of the National Anti-Doping Panel, Zak Hardaker has been charged by UKAD with committing an Anti-Doping Rule Violation (ADVR) under Article 2.1 of the UK Anti-Doping Rules, namely that a metabolite of cocaine was found in a urine sample.
"It was held that the period of Zak's ineligibility to play rugby league should be limited to 14 months. Zak was suspended on September 8 2017, which means he will be eligible to return to play rugby league on November 7 2018.
"Zak's legal team successfully argued that, as a result of a number of exceptional circumstances, the 26-year-old, former England player, bore no significant fault in committing an ADVR."
The legal team added: "We believe the correct verdict has been returned and we would like to thank the tribunal for their professionalism. This was a truly exceptional case, where the drug use was never linked to performance enhancement. In this regard Zak would never take any substance to achieve an unfair advantage and we are pleased that the decision of the tribunal has recognised this fact.
"He was commended by the tribunal for his impressive comprehensive evidence and the fact that he made no attempt to downplay his conduct and was utterly frank with them. The last two years have been an extremely difficult period for Zak who, away from the public eye, has bravely battled a number of personal traumas.
"Zak has asked for privacy at this time but thanked his family and close friends for helping him through this difficult period."
Castleford announced in February that Hardaker had been sacked with four years left on his contract.
The Tigers initially suspended Hardaker last October after dropping the England international for the Super League Grand Final against Leeds, the club he left for Castleford in a loan deal in 2016.
He joined the club on a permanent contract for a fee of £150,000 in June with Daryl Powell's side cruising to League Leaders' Shield success.
But his chequered career took another dark turn when it was revealed he failed a drugs test after a Super 8s game against the Rhinos in September.
In 2014, while at Leeds he was banned for five games after being found guilty of homophobic abuse in a match against Warrington and a year later he agreed to take an anger management course after admitting assaulting a student.
Hardaker was shortlisted for the Man of Steel award he had won in 2015 after recapturing his form in 2017 but he was dropped for the Grand Final and left out of England's World Cup squad following the failed drugs test.
With the help of Castleford, he took a job outside rugby league as he awaited his fate.
Hardaker will now hope to find another club in time for the 2019 Super League season, with Wigan his likely destination.
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