After the war he finished his studies at Columbia University and commenced training for the ordained ministry at the General Theological Seminary.

In 1922, Heistand was ordained deacon and priest by Bishop James Henry Darlington of Harrisburg.

Heistand was elected Coadjutor Bishop of Harrisburg on May 25, 1943, during the 39th General Convention after the third ballot.

He was consecrated on September 15, 1943, by Presiding Bishop Tucker in St Stephen's Cathedral.

His episcopacy is remembered for his work in raising clergy salaries and living conditions while encouraging congregations to meet their financial responsibilities.