When Trinquier's two years of compulsory military service came to an end, he decided to remain in the army and was transferred to the active officers’ school of Saint-Maixent, from which he graduated in 1933 as a second lieutenant.

Trinquier returned to France in 1936 and was assigned to the 41st Colonial Infantry Machine-gun Regiment (41e Régiment de Mitrailleurs d’Infanterie Coloniale, 41e RMIC) at Sarralbe, where he commanded a company until he was sent to China in early August 1938.

When Japan surrendered, the French recovered the weapons that had escaped search and resumed a degree of autonomy, living on credit until the arrival of the "Gaullist" authorities.

He returned to France in the summer of 1946, charged with the responsibility of recruiting and training volunteers for a colonial parachute battalion that was being formed for combat in Indochina against the Viet Minh.

Leading the battalion in combat in central Annam and the area around Saigon, he became aware of the inefficiency of the operations launched by the French high command and proposed to General Pierre Boyer de Latour du Moulin, the commander of the French forces in southern Vietnam, a new approach to pacifying areas with strong Viet Minh presence.

Trinquier took over the command of the GCMA in early 1953 and directed the fighting behind Viet Minh lines, creating a maquis in the Tonkinese upper region and in Laos, totaling around 30,000 men.

Trinquier's maquis contributed to the successful evacuation of the fortified airhead at Na San, in August 1953, and the reoccupation of the Phong Saly and Sam Neua provinces.

After the French withdrawal following the defeat of Dien Bien Phu, Trinquier's maquis was left behind and hunted down by Ho Chi Minh's forces.

Trinquier returned to France in January 1955, being promoted to lieutenant colonel and assigned to the staff of General Gilles, commander of the airborne troops.

He then served as second-in-command to General Massu, commander of the 10th Parachute Division, during the Battle of Algiers, where he was one of the leading figures behind the creation of the DPU (Dispositif de Protection Urbain).

Returning from Congo, when staying in Athens, he learned of the failed Algiers putsch against de Gaulle, after which he asked to be retired from the reserve as well.

In his view terrorists should be treated as soldiers, albeit with the qualification that while they may attack civilian targets and wear no uniform, they also must be tortured for the very specific purpose of betraying their organization.

In the longer term the debate on the tactics used, particularly torture, would re-emerge in the French press for decades to come (with the trial of Paul Aussaresses).

[3] The character of Colonel Jean-Marie la Roncière in another of Larteguy's novels, The Hounds of Hell (Les chimères noires), was certainly based on Trinquier and his activities during the Katanga rebellion.