For nearly a decade, Roberts pastored several Oklahoma churches and preached at revivals while attending college. Then, he said, God spoke to him again, telling him not to be like other men but to "heal the people as He did." Roberts said he could feel the power to heal by the tingling of his right hand.
His first healing service drew 1,200 people, and a few weeks later a healing revival in Tulsa attracted enough people to be extended for nine weeks.
Anecdotal evidence of Roberts' reputed healings made news as many of his followers claimed their ailments had disappeared during a revival. At his first healing service, a German woman reportedly said her right hand, crippled for 38 years, had been restored. Another evening, a blind man is said to have shouted, "I can see! I can see!"
During his ministry, no scientific studies confirmed the evangelist's ability to heal.
Roberts soon began filling up stadiums or huge tents with as many as 25,000 believers.
In a pattern that would continue over the years, his healing ministry was attacked by the media, skeptics and mainstream denominations.
In 1950, Roberts took a big step toward the mainstream of American Christianity when he was invited to say the opening prayer at a Billy Graham crusade after a chance meeting of the preachers at a hotel in Portland, Ore.
"Graham's personal kindness, his glad and wholesome embrace of a fellow Christian, placed Oral momentarily in a larger, more respectable, world than he had ever imagined he could be a part of," according to the 1985 biography "Oral Roberts: An American Life" by David Edwin Harrell Jr.
The preachers remained cordial over the years, though Roberts could never match the good press that Graham received.
Roberts came in for criticism in the 1950s when, occasionally, a worshiper would die during a crusade. Ministry spokesmen said the deaths were not unusual considering how many sick people were in attendance.
The minister was controversial for other reasons as well. In the days of segregation, Roberts, like Graham, insisted that black and white worshipers sit together, a progressive policy he said brought him death threats.
"We didn't think of being ahead of our time," Roberts recalled.
In 1954, Roberts became one of the first televangelists, taping his crusades and then airing them on TV stations across the nation. Within a year, his programs were being carried by more than 200 stations.
At the end of each show, Roberts didn't ask for money but told viewers to send a letter to Oral Roberts, Tulsa, Okla.
One of the challenges of his booming enterprise was how to handle the thousands of letters that poured in each week. Again a trailblazer, he worked with IBM to develop one of the first computerized systems to immediately send out seemingly personalized letters.
Among the projects he financed this way was what was initially called the Oral Roberts University of Evangelism. His original idea was to train foreign students to spread the Gospel throughout the world. That evolved into a vision of a full-scale university that would combine Bible teaching with academic and athletic programs.
Oral Roberts University opened in 1965 with 300 freshmen, and in 1971 the 263-acre college was accredited.
As the end of the 1960s approached, Roberts' crusades drew dwindling numbers. A final blow came in 1968, when Roberts shocked his followers -- and the Pentecostal Holiness Church, sponsor of his events -- by becoming a Methodist minister.
His shift to the Methodists allowed him more leeway in mixing secular elements like dancing into his television shows and represented another move toward the mainstream and a larger flock to lead.
Roberts ended his crusades and his long-running television show in 1968. The following year, he launched one-hour prime-time specials centered around celebrities such as Pat Boone, Dale Evans, Anita Bryant, Robert Goulet, and Johnny and June Carter Cash.
Although many of Roberts' longtime supporters were appalled by what they saw as the secularization of Christianity, within three years nearly 40 million viewers were tuning in to the prime-time specials and they, along with his weekly Sunday show, generated 760,000 letters a month -- a gold mine of potential donors who were added to Roberts' increasingly sophisticated direct-mail database.
By this time, he had abandoned the flashy suits of his tent revival days in favor of tailored clothes.
In 1970, he published "The Miracle of Seed-Faith," which promised financial riches for those who gave to God -- which he called planting a seed of faith.
In 1975, Roberts announced plans for the university to build medical, dental and law schools. The annual budget for Oral Roberts Evangelical Assn. -- his umbrella organization -- approached $40 million.
But the first of a series of family tragedies struck in 1977 when Roberts' 37-year-old daughter, Rebecca, and her husband, Marshall Nash, died in a plane crash, leaving three children.