American Catholic priest, sociologist, theologian and author of racy bestselling novels such as The Cardinal Sins
Once described by America's National Catholic Register as "the dirtiest mind ever ordained", Father Andrew Greeley, who has died aged 85, was a prolific writer who found that his bestselling popular fiction often overshadowed his serious work on theology, politics and society. As arguably the most visible voice of Catholicism in America, he assumed the position of prophet without honour within a church he often saw as corrupt and unresponsive to the needs of its laity. Although he was possibly America's most influential Catholic sociologist, Greeley himself recognised that he was more likely to be remembered for his fiction, forecasting that his obituary would be headlined "Andrew Greeley, priest: wrote steamy novels".
The best known of those nearly 70 novels was his third, The Cardinal Sins (1981), which follows the paths of two childhood friends who become priests, one of whom fathers a child. It sold some 3m copies.
Greeley followed it up with his Passover Trilogy, an Irish-American family saga which, as he explained, dealt with "adultery, incest and sacrilege". Hitting his stride, Greeley for 22 years published at least two, and sometimes as many as four, novels a year.
These included two mystery series. The first, featuring Monsignor John Blackwood "Blackie" Ryan, and often concerned with seemingly supernatural events and locked-room murders, began with Happy Are the Meek (1985). After seven more novels whose titles reflected the Beatitudes, Ryan became a bishop. The Bishop at Sea (1997) was the first of seven more books with "bishop" in the title, and, although it too had a ghost and a locked-room murder, it was more concerned with the covering up of abuse of women in the military, metaphorically a reflection of Greeley's own concern with the church covering up its own child-abuse scandals.
Asked to explain his prolific output, Greeley said: "I suppose I have an Irish weakness for words gone wild. Besides, if you're celibate, you have to do something." His 12-novel series about Nuala Anne McGraill, an Irish detective with sixth sense, began with Irish Gold (1994) and always had Irish in the title. Greeley's fictional concerns stayed close to his own life, which was centred on the church, Irishness and Chicago.
Greeley, the grandson of Irish immigrants, was born in Oak Park, a Chicago suburb, and grew up in nearby Austin. He decided to become a priest before he was 10, and attended a preparatory seminary before taking three degrees in sacred theology from St Mary of the Lake in Chicago. He was ordained in 1954 and for 10 years was an assistant priest at Christ the King in the city, publishing his first book, The Church in the Suburbs, in 1958. Meanwhile, he studied at the University of Chicago, receiving an MA and PhD in sociology. His doctoral thesis, about the influence of religion on the careers of college graduates, was published as Religion and Career (1963). He taught briefly at the Universities of Arizona and Illinois-Chicago before returning to the University of Chicago, while directing research at the National Opinion Research Centre.
Eventually he would publish more than 80 works of non-fiction. The concerns of his early books were the positions of the church in society, of priests within both the church and society, and the effects of Catholic education. In the former two areas, Greeley was firmly in the liberal camp, influenced profoundly by so-called liberation theology, but on education he was conservative, promoting the values of parochial (ie church) schools, and he was a defender of priestly celibacy. His response to Pope Paul VI's 1968 encyclical, Humanae Vitae, which prohibited Catholics from using birth control, was the first to warn of the widening gulf between Catholics and church authority. It began his own battle within the church.
In 1972, Greeley was commissioned by the US bishops' council to investigate morale among Catholic clergy. He reported that it was dangerously low, and blamed the church hierarchy. When the bishops supressed the report, Greeley believed Cardinal John Cody, of Chicago, was behind it. The deeply conservative and controversial Cody had refused Greeley his own parish and closed inner-city parochial schools, which Greeley strongly opposed. In the midst of this, Greeley was also refused tenure at the University of Chicago. He once called Cody "one of the most truly evil men I have ever known".
In the wake of these controversies, Greeley turned to fiction with The Magic Cup (1975), a fantasy about a king leading Ireland from paganism to Christianity. The church, and then the state of Illinois, began investigating Cody for diverting money into a slush fund, some of which he used to support a female partner. Although Greeley always denied it, this was probably the core of The Cardinal Sins. Cody died in 1982, the year after the novel was published but before any investigations were completed.
Greeley became a columnist with the Chicago Sun-Times and a prominent supporter of local sports teams the Bears, Bulls and Cubs. He was an early and vocal advocate for victims of priestly abuse and his novel The Priestly Sins (2004) was about a priest persecuted by the church for fighting its cover-up. In 2005 he published The Making of the Pope, an excellent analysis of Cardinal Joseph Ratzinger's election as Pope Benedict XVI.
His writing made him wealthy, and he lived in a luxury apartment in Chicago's Hancock Tower, but he was a great philanthropist, particularly to Catholic education charities. Greeley was also an early donor to Barack Obama's presidential campaign, although he did not expect Obama to succeed. His last non-fiction book was his most overtly political: A Stupid, Unjust and Criminal War: Iraq 2001-2007.
In 2008, Greeley suffered a fractured skull when his coat was caught in the door of a cab pulling away; he was left unable to write, and his condition deteriorated. Accused of "never having had an unpublished thought", his response was simple: "Why should I practise contraception on my ideas?"
• Andrew Moran Greeley, priest, author and sociologist, born 5 February 1928; died 29 May 2013