He graduated from the University of the South at Sewanee, Tennessee, and its divinity school, then called St. Luke's Seminary, in 1945.

He served churches in Arkansas and Louisiana before becoming rector of All Saints' Junior College in Vicksburg, Mississippi, in 1958, a post he retained till 1961.

[1] In 1978, he offered to resign because of his opposition as a theological conservative to women's ordination, but he was persuaded to remain in office.

He was the last Presiding Bishop of the Episcopal Church to have opposed women's ordination and held a pro-life stance.

[2] After his term as Presiding Bishop, Allin was vicar at St. Ann's Episcopal Church in Kennebunkport, Maine, where his friend George H. W. Bush was on the vestry.