In September 2013, a judge in Riverside, Calif., sentenced Pocklington to six months for violating a term of his probation on a perjury conviction.
Pocklington filed an appeal later that year.
On Thursday, the Ninth U.S. Circuit Court of Appeals reversed the ruling, saying the judge lacked jurisdiction.
Pocklington is notorious in Canada for bringing Wayne Gretzky to the Oilers in the 1970s, then trading the superstar a decade later to the Los Angeles Kings.
He praised his lawyer Becky James for winning the appeal, but declined further comment.
"She knew I had been wronged," Pocklington, 73, said in a release Friday. "She was determined to win, and she did."
Court heard that Pocklington had submitted a false monthly income report to his probation officer — he hadn't adequately disclosed a $15,000 consulting fee he received in January 2012.
The appeals court said the judge lacked jurisdiction to extend Pocklington's probation that was part of a sentence that was imposed in 2010 after he pleaded guilty to perjury.
"The district court lacked jurisdiction to extend Pocklington's probation beyond its October 26, 2012, expiration date," the appeal court panel said in a written ruling released Thursday.
"We vacate the September 13, 2013, order revoking Pocklington's probation and sentencing him to six months in prison and two years of supervised release."
Pocklington filed a bankruptcy claim in 2008 stating he was virtually penniless and owed almost $US20 million.
He eventually admitted in court that he hadn't disclosed that he had control over bank accounts and storage facilities containing assets and property belonging to his wife.