The Svea court of appeals sentenced Sunde to eight months' in prison for promoting copyright infringment in November 2010.
In February, the Supreme Court announced it would not be hearing the case against the Pirate Bay founders.
Sunde was to start serving his prison sentence on Wednesday, but decided instead to ask to be pardoned by the government.
In a letter to the justice ministry, Sunde's legal representative cited health issues and work on a new website for micropayments, Flattr, as reasons.
Sunde's three co-founders, Fredrik Neij, Gottfrid Svartholm and Carl Lundström, have all been sentenced to prison along with Sunde.
In addition, all four were ordered to pay nearly $US 7 million worth of damages to the film- and music industries.