William E. Jessop filed papers with the Utah Department of Commerce to take over as president of the corporation that is the Fundamentalist Church of Jesus Christ of Latter Day Saints.
Jessop, who served as bishop of the twin FLDS border towns of Hildale, Utah, and Colorado City, Ariz., said Monday his rise to the presidency is not an attempt to take over the church, but rather the fulfillment of an earlier directive from Jeffs.
"It is an attempt to preserve ... the church," Jessop, 41, said in an interview with The Associated Press.
It remained unclear whether Jeffs would immediately lose all power in the church or share it with Jessop, at least for now.
Jeffs has not filed papers with the state indicating he had plans to resign. However, he would not have to formally step down as the church's president for Jessop to be installed, Commerce Department spokeswoman Jennifer Bolton said Monday.
An attempt to reach Jeffs at the Texas jail where is being held was unsuccessful Monday, and a telephone call to his criminal attorney was not immediately returned. A message left for Rod Parker, a Salt Lake City attorney who represents the church in civil matters, also wasn't returned.
Jeffs, 55, was convicted in Utah in 2007 on two felony counts of rape as an accomplice and was ordered to serve life sentences, but the convictions were later overturned.
Earlier that year, while jailed and awaiting trial, Jeffs tried to cede authority of the church -- both as president and spiritual leader -- to Jessop in a series of recorded telephone calls to followers and to Jessop, himself.
"I know of your ordination, that you are the key holder, and I have sent a note with my signature so that there is no question," Jeffs told Jessop in a Jan. 24, 2007, telephone call from a Utah jail.
The tapes and a DVD of the conversations were released by the court as part of Jeffs' trial.
Jessop did not respond to the offer at the time, and Jeffs publicly remained spiritual head and president of the church. Other church members speculated the calls from Jeffs were merely a test of their faith.
Four days later, Jeffs attempted suicide by trying to hang himself in the jail.
Then in December 2007, after his Utah conviction, Jeffs resigned as president of the church corporation, believing he could no longer run its day-to-day business from behind bars. But he remained the group's spiritual leader.
Jeffs was later moved to a jail in Texas, where he is awaiting trial on bigamy and aggravated sexual assault charges. Last month, he retook control of the church following the abrupt resignation of his replacement, who was forced out of the church.
Jessop said he is only stepping forward now because he believes he can help provide the church with the leadership it needs while Jeffs is incarcerated.
"We take things at Heavenly Father's pace," said Jessop, who listed a Colorado address on the Commerce Department paperwork.
Jessop's assertion of leadership is largely unprecedented, and it wasn't immediately clear whether the move would fracture or unite the 10,000-strong church with members in Arizona, British Columbia, Colorado, South Dakota, Texas and Utah.
Asked if he is now considered the church's prophet and spiritual leader, Jessop said that will be up to individual church members. In the past, the church president has also been considered its prophet.
Meanwhile, a trial for Jeffs is set for later this year in Texas, where prosecutors allege he had sex with two girls, one under age 14 and one under age 17. A court has entered not guilty pleas on Jeffs' behalf.
Canadian authorities also are investigating allegations that in 2005 Jeffs married two 12-year-old sect girls who were brought from a church enclave in British Columbia to the U.S. It's not clear whether those girls are the same victims whose relationships with Jeffs are the basis for the Texas charges.
Jeffs assumed the role as FLDS prophet and president in September 2002 following the death of his father, Rulon Jeffs, who suffered a series of strokes.
His rise to power has been questioned by former church members who say there was no succession plan in place when the elder Jeffs died because he had preached that the second coming of Jesus Christ was imminent, and therefore no one would need to lead the church in the future.
The FLDS practices polygamy in marriages arranged through church leaders. Historically some unions have involved underage girls, although following a 2008 raid on the church's Eldorado, Texas ranch, a church spokesman said the faith had halted the practice.
The faith's religious roots are tied to the early teachings of Joseph Smith who founded the mainstream Mormon church. Smith's church abandoned the practice of plural marriage in 1890 as a condition of Utah's push for statehood and excommunicates members found practicing it.