It's important to remember that harkis is not an umbrella term for all Algerian men who served under the French flag during the Algerian War. The harkis was a very specific unit while the mokhaznis, the militiamen, served alongside the SAS (Section Administrative Spécialisée - a Civic Action unit). For this, however, I will focus on the harkis.

The majority of the harkis were from a rural background due to the nature of the conflict, the counterinsurgency was waged outside of urban centres (with a few exceptions). Both Arabs and Berbers served as harkis. The motivation of the harkis was something that can not boil down to a single reason. At the height of 1958, a total of 60,000 harkis were in French service and all served for different reasons. Some reasons were financial: the promise of a recurring wage to support their families. Others were as simple as a genuine identification with France, for revenge due to family members or friends being killed by the ALN to not being accepted into the ALN and thus turned around completely and join the French Army instead. It is interesting to note that no system of conscription of Algerians were in place, but that there were those who defected from the ALN and joined the harkis as well as those who were forced under threat of reprisals to join the harkis by the French Army. The motivations and reasons are plenty and one could imagine that every harkis has a story of his own to tell about his own involvement.