He has served as prime minister during a time of transition before.
After General Robert Guei's coup in 1999, he took the reins until elections were held in October 2000, which ousted the military junta.
As a Muslim from the north of the country, 69-year-old Mr Diarra's appointment will be seen as a sign of appeasement to the rebels who seized much of the north in the four-month civil war.
Mr Diarra's background as a technocrat makes him an obvious choice to lead the interim government.
Cocoa boss
After winning a scholarship to study agriculture in France, he returned to Ivory Coast shortly after independence to run a state-run agriculture co-operation and insurance body.
There he got on the wrong side of the authorities and was jailed for what the government saw as agitating by trying to set up co-operatives.
PEACE DEAL
But he was soon rehabilitated and went on to run the government organisation in charge of Ivory Coast's main industry - cocoa.
This was followed by a series of high-level posts - African representative to the International Coffee Organisation, ambassador to Brazil, the European Union and finally the UK.
He returned to Ivory Coast to run his own business as a cocoa exporter.
Rebuilding work
Despite being chosen to lead the military government, Mr Diarra was not seen to be compromised in the eyes of President Gbagbo's administration.
Instead, he was appointed head of a short-lived national reconciliation forum, aimed a resolving ethnic tensions inside the country.
But despite his efforts, a failed coup against Mr Gbagbo fanned those smouldering tensions into all-out conflict.
In his new role, Mr Diarra will have to try to mend the rifts which that conflict has created and restore his country's reputation as one of West Africa's more stable nations.