The Associated Press noted that Romney spent 14 years serving as a lay Mormon pastor in Massachusetts — where he also served as Governor — counseling church members and "immigrant converts from Haiti, Cambodia and other countries" on their personal lives.
According to Romney's son, Tagg, the candidate's prior reticence to speak about his religionhas itself been an expression of his faith. "One of the tenets of our faith and of many faiths is that you do good works. (But) you don't want to brag about things," Romney's son told Politico.
Of course, the Mormon church's minority status in the US and mystery surrounding its practices may have also made it politically complicated to discuss on the campaign trail.
The Church of Latter-day Saints, founded in the 1830s in New York state, has clearly played a major role in the life of the Republican presidential nominee. That makes him unique among Americans, less than 2 percent of whom identified as Mormon five years ago, according to 2007 data collected by the Pew Forum on Religion & Public Life.
In a 2007 article, the Economist noted that Mormonism was declining in America, but otherwise gaining traction "in virtually every country in the world." According to a 2012 Reuters article, the US decline still holds.
But, "there is hardly anywhere (not even Mongolia, see picture) where the proselytisers do not reach," the Economist wrote.
How widely does the faith extend around the globe?
There are 14.4 million Mormons worldwide, according to the Guardian. With the prominent exception of the Philippines, Mormonism is most prevalent in the Americas. After the US, Mexico, Brazil, the Philippines and Chile have the highest absolute numbers of members, according to a 2005 report by the Church of Jesus Christ of Latter-day Saints. Peru, Argentina, Guatemala, Canada and Ecuador follow.
A 2009 Reuters article wrote that "the Mormon flock is flourishing in Latin America, especially in Mexico and Brazil," its popularity helped along by a "wholesome, family-oriented image."
The current fleet of Mormon missionaries, according to the Guardian, numbers 55,000 worldwide at any given moment. International missions are central to the practice of Mormonism.
In the 1980s, sociologist Rodney Stark wrote that Mormonism was becoming "the first major faith to appear on Earth since the Prophet Mohammed rode out of the desert," according to the Salt Lake City Tribune.
Scholars and researchers have debated whether Mormonism is a "global" or a "world" religion, a distinction made by whether the faith has been integrated into a host country's culture. World religions are integrated, while global are not.
The Economist argued in 2007 that Mormonism hasn't fully attained the integrated status, still retaining a "Middle Western flavor, with its mixture of social conservatism, philanthropy, worldly shrewdness and devotion to a core set of beliefs."