Paul Anthony Formosa, who was the construction project manager for DP World, was killed near Bossasso port.
Islamist militant group al-Shabab has said it carried out the attack.
Puntland, an arid region of north-east Somalia, declared itself an autonomous state in 1998, in part to avoid the clan warfare in southern Somalia.
The state is a destination for many Somalis displaced by violence in the south. More on bbc