"I have had to establish relationships with killers and with the families of their victims, with arms smugglers, corrupt officials and more," he once said.
In 2007 he was appointed dean of Liverpool Cathedral, Britain's largest church, and in November last year he was elevated to Durham, the fourth-ranking diocese in the church of England.
His business background still serves him well, Welby has said.
"Treasury teaches you to be decisive. Markets don't allow you to hang about and vacillate," he said in an interview in The Treasurer, the magazine of the Association of Corporate Treasurers. "And treasury teaches you about teamwork and working collaboratively. In treasury you are there to serve the company and the operating departments."
Welby and his wife Caroline have two sons and three daughters. Their first child, a 7-month-old girl, was killed in a traffic accident in 1983.
AP religion writer Rachel Zoll in New York contributed to this report.