On 15 September 1929 Father Pinault embarked on his mission to Chengdu, China. When he first arrived in China the country was in turmoil. After spending several months in Chengdu, he was sent to Bazhou to undergo language training. Father Pinault took the Chinese name Peng Daochuan. The city was captured on 23 February 1933 by forces of the Communist Party of China and clergymen and Christians were forced to flee. Father Pinault found refuge with Benedictine monks in Chongqing. In 1934 Father Pinault was appointed Supérieur du Probatorium at Hebachang, where he organized a hospice in 1942. In 1945 Father Pinault departed from Hebachang and replaced the deceased pastor at Tsong-Kin-Tcheou. On 14 July 1949 Pinault was appointed to replace the late Jacques-Victor-Marius Rouchouse as Bishop of Chengdu, the highest post in the Roman Catholic Diocese of Chengdu in the Ecclesiastical province of Chongqing; Bishop Pinault received his episcopal ordination on 21 September 1949. Only two months later, on 28 December 1949, the city of Chengdu was captured by communist forces. In order to protect his fellow clergy members, Bishop Pinault took personal responsibility for the ownership of all church property. This act placed him at risk as Communist Party administrators placed heavy taxes on religious properties and imprisoned clergy members. Officials ruled that Bishop Pinault was unable to pay his “debts” and threw him in prison in early 1952, where he underwent repeated interrogations. Finally, Bishop Pinault was expelled from China, leaving Chengdu on 29 March 1952 and arriving in Hong Kong on 14 April. Bishop Pinault arrived in Marseilles on June 30 and shortly after visited his mother in Évran. After his departure from China, Pinault retained the title of Bishop of Chengdu, which he would hold until 1983.
Shortly after his arrival in France, Bishop Pinault accepted an assignment as a military chaplain in the French Air Force in North Africa. On 29 December 1953 Bishop Pinault returned to France and spent time at Voreppe before relocating to Paris, working with la Mission bretonne and the ministère épiscopal de Confirmations et d'Ordinations. Bishop Pinault took part in the Second Vatican Council in Rome from 1962-1965. On his return from Rome, Bishop Pinault retired to Évran, where he lived with his mother, who died in 1975, and served neighboring parishes. In June 1980, Bishop Pinault celebrated Eucharist in Lisieux with Pope John Paul II during the Pope’s pilgrimage. In 1983, Pinault retired from his position as Bishop of Chengdu and became its Bishop Emeritus; the position of Bishop of Chengdu was left vacant. In December 1986 Pinault was hospitalized at Rennes with arteritis and underwent several surgeries. He returned home to Évran on 23 February but at 6:00 p.m. on 24 February 1987 he died. He is buried next to his mother in a small cemetery in Évran.
