Sibusiso Gcabashe was found guilty of a string of charges, including kidnapping and raping an 18-year-old woman.
Gcabashe was also convicted of impersonating Khulekani "Mgqumeni" Khumalo, who died in 2009.
Thousands of fans flocked to his house in KwaZulu-Natal in 2012 believing he had been resurrected.
He was an award-winning "Maskandi" musician.
Three years after his death, Gcabashe returned to the singer's hometown, claiming he had been kidnapped by a witchdoctor who had cast a spell on him and held him in a cave with zombies.
His fingerprints proved he was not the singer, police said at the time.
Gcabashe, 32, was found guilty of rape, assault, kidnapping, attempted escape from lawful custody and impersonating Khumalo.
He underwent psychiatric evaluation during the course of his lengthy trial but was found fit to face justice, says the BBC's Pumza Fihlani in Johannesburg.
The magistrate who convicted Gcabashe said he didn't show any remorse during the trial.
Even Khumalo's own family appeared split over his identity. While his wives believed he was their husband returned from the dead, a former lover was not convinced.
Some of Khumalo's family said they would appeal against the conviction in the High Court because they still believed Gcabashe was indeed their son, according to local reports.
Belief in witchcraft is not uncommon in rural South Africa.
The man apparently sang one of Khumalo's song as he was being escorted to the police cells and said he would compose music in prison, according to SABC news.
A man who made headlines for impersonating a dead Zulu folk musician has been sentenced to 28 years in prison.