"My faith and political beliefs are deeply intertwined. I am a Democrat because I am a Mormon, not in spite of it," he told a gathering of over 4,000 at the Marriott Center.
But Nevada's senior senator says he also hopes votes for Republican presidential candidate Mitt Romney are "determined by his political stands, and not his religion."
Reid said people often question how he can be a Democrat and a Mormon, but called the social responsibility Democrats espouse a good fit with the beliefs of The Church of Jesus Christ of Latter-day Saints.
He questioned the guidance of some LDS Church leaders, though.
In remarks to the media following his address, Reid said that, "In the past years we've had some very prominent members of the church, like Ezra Taft Benson, who are really right-wing people.
"Members of the church are obedient and followers in the true sense of the word, but these people have taken members of the church down the path that is the wrong path," he said.
However, Reid says he doesn't have to answer to those who question his faith in the LDS Church.
" I have to go get my [temple] recommend, and they're not present," he quipped.
Reid didn't convert to the LDS Church until later in life, after he married his wife, Landra, both of whom were 19 at the time.
Before joining the church, he said the figure he came closest to worshipping was President Franklin D. Roosevelt. A pillowcase with the quote "We can, we will, we must" stitched on it hung in his living room growing up in Searchlight, Nev., in a house with no indoor plumbing.
"He fought for the workers of America," Reid said. "President Roosevelt is the basis of my political direction."
Reid praised workers' unions, condemned the thought that free enterprise alone can solve global warming and spoke out strongly against the war in Iraq.
"I say the invasion of Iraq was the worst foreign policy blunder in our country's history," he said to loud applause from many in attendance. "I say our diplomatic army should be larger than our military army."
Reid said afterward that the reaction did not surprise him because many Americans oppose the war, including BYU students.
While Reid is a Democrat, he says he is adamantly anti-abortion, and instead of voting for abortion bills, he votes for family-planning measures such as federal health insurance programs covering contraceptives, he said.
Katherine Winters, a graduate student in civil engineering, said she was happy to get beyond the typical sound bites and begin to know Reid "as a person."
She said she originally registered as a Republican when she turned 18 because her parents were Republicans. But lately she's been rethinking her political positions.
"Recently there's so much that the Democratic Party has embraced; there is so much good that those social causes have done," she said. "I don't think you can call yourself a true Christian without caring for the poor."