Obituaries and other biographical collections on the life and religious history of Hurley stress the fact that he was a staunch opponent of the apartheid policy and of relevance to the Namibian context. He at some point publicly denounced the barbaric acts committed by the South African special insurgency unit Koevoet, against black people in the northern part of the country.
Hurley was born in Cape Town, South Africa to Irish parents. He spent his childhood years at Robben Island where his father is noted to have been a lighthouse keeper.
In 1931, he joined the Missionary Oblates of Mary Immaculate, which eventually saw him sent to Ireland a year later for his novitiate.
In 1933, he was sent to the former Anglicum University in Rome to study philosophy and theology.
There, he obtained a degree in philosophy in 1936 and went on to study at the Gregorian University. On the 9th of July 1939, he was ordained as a priest and was later appointed as curate at Emmanuel Cathedral, Durban.
At the age of 36, on the 11th January 1951, Hurley became the Vicar Apostolic of Natal and Bishop of Durban. In the following year he became President of the Southern African Catholic Bishops Conference.
Even though his struggle for justice and peace goes back to the 1940s, it was particularly after he became president of the South African Catholic Bishops Conference that he began to take a formidable role in the struggle against apartheid, both in Namibia and South Africa.
Citing Hurley's stance against the apartheid administration in Namibia, Paddy Kearney in the biography entitled, "Archbishop Denis Hurley: A Short Biography", wrote: "As president of the Bishop's Conference for the second period from 1981 - 1987, Hurley was once again in the national limelight. During these years Hurley's leadership was key to major reports published by the conference highlighting the situation in Namibia (then called South West Africa)."
The reports noted to have been published under Hurley's leadership condemned issues such as forced removals and most importantly the use of extensive violence by Koevoet in the northern part of Namibia.
Writing Hurley's biography, Kearney further argued: "As a result of the comments he made at the launch of a report on Namibia, he was charged with libeling the anti-insurgency unit known as Koevoet (crowbar)."
The South African colonial administration charged him under the 1958 Act for allegedly making unsubstantiated claims that Koevoet was involved in illegal killings and beatings in Namibia.
Nonetheless, the charges were dropped in 1985 just a day before he would go to Court. Other commentators on Hurley's biography argue that the charges were only dropped after it became clear that "Hurley would be able to prove the truth of his statements."
Kearney is of the opinion that the South African government only dropped the charges after it realized that "they were taking on a formidable opponent with widespread local and international support, whose prosecution will only draw attention to the illegality of South Africa's presence in Namibia and the gross human rights abuses of which its security forces are guilty."
His advocacy for peace, justice and public criticism of the apartheid system earned him a reputation as the worst enemy of the apartheid administration. His biography cites that at some point he received "death threats not only from agents of the government, but also, it was suspected, from deeply conservative white members of the Catholic Church."
In one incident his house was petrol-bombed.
Hurley is noted to have retired as Archbishop of Durban in 1992 and died on the 13th of February 2004.