The court found Mohammed, the son of Somalia’s President Hassan Sheikh Mohamud, guilty of causing death by negligence when the car he was driving collided with a motorbike delivery man on November 30.
Yunus Emre Gocer, the delivery man and a father of two children, died in hospital six days later.
Turkish prosecutors issued an international arrest warrant after police discovered that Mohammed had left the country after the incident.
His departure caused an outcry in Turkey's opposition media, which accused the government of allowing Somalia’s first son to escape prosecution in order to preserve good relations with its close African ally.
An Istanbul court on Tuesday handed a prison sentence of two years and six months to the suspect, converting it into a $900 fine, the private NTV broadcaster reported.
Turkish prosecutors had sought a prison sentence up to six years.
Mohammed returned to Istanbul to testify in the case, Turkey's pro-government media reported, although it was not immediately clear if he was in court when the verdict was read.
Turkey has had close relations with Somalia for the last 10 years and is the Horn of Africa nation's leading economic partner, notably in the construction, education and health sectors.
The two countries also enjoy close military ties.