Pal was released after Turkmen President Gurbanguly Berdymukhammedov signed a decree granting amnesty to him on the eve of Neutrality Day, usually marked in Turkmenistan on December 12.
Pal is a computer engineer who assisted Turkmen rights activists in using Internet technology to distribute information from Turkmenistan around the world.
He was detained in February and found guilty of embezzlement three months later. Pal was sentenced to 12 years in prison.
More people are expected to be released due to the presidential decree.
Farid Tukhbatulin, chairman of the Turkmen Initiative for Human Rights, a Turkmen group working in exile in Europe, was quoted by Reuters as saying Pal "is seriously ill, but at least he is at home now."
The nature of Pal's illness is not clear.
Pal's release comes ahead of December 14 parliamentary elections in Turkmenistan, a one-party state that tolerates no dissent but which says the vote will highlight its commitment to democratic reform.