File Photo: Kurdish political prisoner Heidar Ghorbani. (Photo courtesy of Twitter)
Mohayyedin Ebrahimi was hanged at dawn at Urmia prison in northwestern Iran, the Norway-based Iran Human Rights (IHR) and Hengaw rights groups said in separate statements.
Five other men were also executed on drug-related charges at Urmia on Friday morning, the groups added.
Ebrahimi, arrested in 2017 and sentenced to death in 2018, was accused of involvement in the Kurdish Democratic Party, a banned group that has waged an armed struggle for self-determination of Iran's Kurdish-populated region.
Ebrahimi denied the charges, with rights groups saying that he had only been working as a porter carrying goods from Iraq.
Both IHR and Hengaw described him as a "political prisoner".
IHR said a protest took place outside the doors of Urmia prison late on Thursday after it became apparent his execution could be imminent, and his son was arrested.
Hengaw said Ebrahimi's family was initially told he was moving to another prison after the sentence was suspended, only to be called to collect the body.
Meanwhile, another convict was hanged on Thursday in the prison of Khorramabad in western Iran for the murder of a policeman, the official IRNA news agency said.
The hangings come as alarm intensifies over the high number of executions in Iran, which has also faced strong international condemnation over its crackdown on a protest movement that erupted in September.
Iran has executed four people over the protests, sparked by the September 16 death of Mahsa Amini, a 22-year-old Iranian Kurd who had been arrested for allegedly violating the strict dress rule for women.
Rights groups have warned that executions on all kinds of charges are on the rise, arguing this seeks to intimidate society into not protesting.
According to IHR, at least 144 people have been executed this year.
IHR director Mahmood Amiry Moghaddam described those executed "as victims of the government's execution machine, whose purpose is only to intimidate people and prevent protests."
Amnesty International has accused Iran of a "chilling escalation in the use of the death penalty" with the Kurdish and Baluch ethnic minorities particularly targeted.