The Alberta Court of Appeal issued a decision Monday directing an acquittal verdict for the Edmonton man, whose name was withheld, the Canadian Broadcasting Corp. reported.
The network said the man's 9-year-old stepson, now an adult, said his biological father forced him to lie about the sex abuse by threatening him with a knife. At the time, the boy's biological parents were engaged in a custody fight.
The stepfather was convicted in 1995 and served his entire sentence, having been denied parole because he refused to admit guilt.
While the man was still in prison, the stepson told his mother he had lied, prompting a slow-moving review that ultimately led to the stepfather's acquittal.
The stepfather's attorney told the CBC his client is relieved by the outcome, is back with his common-law wife and is on good terms with his stepson.