The contestant from the 2007-2008 season made the announcement during a Christmas concert Monday in downtown Salt Lake City, according to KSL.com. The 20-year-old Miami native, who grew up in Utah, said he's not quitting music, but feels a strong call to serve the church.
A video of the concert on Archuleta's website shows him overwhelmed with emotion and crying as he talks about his plans. The crowd screams wildly with the news and gives him a standing ovation.
"It's not because someone told me that I'm supposed to do it, and not because I no longer want to do music, but because it's the feeling that I've felt I need to do this with my life," Archuleta told the crowd.
Archuleta was 16 and one of the youngest contestants when he competed on the seventh season of "American Idol." The runner-up has since released three albums, one of which debuted at No. 2 on the Billboard 200 chart.
In 2010, he performed with the Grammy-winning Mormon Tabernacle choir at the group's annual Christmas concert.
Church spokesman Eric Hawkins confirmed that Archuleta had been called on a mission by the faith. Hawkins said he didn't know when Archuleta was scheduled to report for missionary training.
The location of Archuleta's mission has not been disclosed either by him or church officials.
Statistics released in April show the church has more than 52,200 members currently are serving full-time proselytizing or service missions worldwide. About 75 percent of missionaries are men between 19 and 21. Single women over 21 and retired couples make up the remaining 25 percent.
Single men typically serve for two years, and women and couples serve for 18 months.
Missionaries volunteer for service, but must be selected by program officials in Salt Lake City. They are not paid and must cover their own expenses while in the field.
The church has more than 350 missions worldwide.