Rimbault served with the Loyal Regiment (North Lancashire) during the Second World War, seeing action in North Africa, Anzio, Italy and Palestine. He held several commands during the course of the war, including as commanding officer of the 1st Battalion The Loyal Regiment. He was awarded the Distinguished Service Order in the 1945 Birthday Honours for gallant and distinguished service during the Italian Campaign. He was promoted to the rank of major after the war in July 1946. He was made a brevet lieutenant colonel in July 1951, with him obtaining the full rank in August 1952. He was made a CBE in the 1954 Birthday Honours. He was promoted to the rank of colonel in December 1954, with promotion to the rank of brigadier coming in June 1958. In February in 1959, he was made the regimental colonel of the Loyal Regiment, a ceremonial position he would hold until 1970.