Navid Afkari's family members and acquaintances gathered at his burial place, in Sangar village of Sepidan city in Fars province, to shower his grave with flowers.
A video of the ceremony circulated on social media shows dozens of attendees chanting, "Navid, the Champion."
Afkari, an Iranian national wrestling champion, was sentenced to death on charges of participating in the widespread protests in August 2018 and allegedly killing a security guard.
Iran's Ministry of Intelligence and Judiciary accused Afkari of the murder of Hassan Torkman, a secret security agent of the Islamic Revolution Guards Corps (IRGC), who was assigned to suppress the protesters in Shiraz, south of Iran.
Torkman's body was officially buried as a "martyr" by the regime, signifying his position. During the widespread protests in 2018, Torkman worked as a security guard for the Water and Sewage company (ABFA) of Shiraz.
While Afkari's family and attorneys were negotiating a pardon for him, the security forces in the notorious Adelabad prison in Shiraz hanged the 27-year-old wrestler on September 12.
Before his execution, and in several audio files leaked out of prison, Afkari had repeatedly denied killing Torkman and insisted that he had been forced under torture to admit to the crime.
Afkari's elderly mother, Bahiyyeh Namjoo, also said in a video posted on social media on August 30 that her son and two of his brothers had been severely tortured behind bars to confess against each other.
According to the court ruling, Vahid Afkari was sentenced to 54 years and six months in prison and 74 lashes, and his brothers, Habib Afkari, to 27 years and three months in jail and 74 lashes.
Afkari's body was buried in a secret ceremony, closed to the public, on September 12.