Jack Ely, best known for his 1963 rendition of the song "Louie Louie," in 2009. (Don Ryan/AP)

Jack Ely, the lead singer and rhythm guitarist of the Kingsmen, whose 1963 recording of “Louie Louie” became a defining song of the garage rock movement and whose unintelligible lyrics drew FBI scrutiny, died April 28 at his home in Redmond, Ore. He was 71.

His son Sean Ely confirmed the death but did not disclose the cause.

“Louie Louie” was a three-chord rock song written and recorded in the late 1950s by Richard Berry, and its story involved a sailor telling a bartender named Louie that he wants to sail back to Jamaica and the girl he loves.

With its infectious rhythm and facile chord changes, “Louie Louie” was the first song many aspiring teen bands learned. The band Rockin’ Robin Roberts and the Wailers recorded it in 1961.

But it was the Kingsmen’s version that garnered huge attention, reaching No. 2 on the Billboard charts despite being banned from many radio stations. Mr. Ely’s garbled rendition of the lyrics were rumored to contain obscenities.

When an alarmed parent sent a letter to then-Attorney General Robert F. Kennedy, the FBI stepped in to investigate the lyrics. After a probe lasting 31 months, the law-enforcement agency concluded that it was “unable to interpret any of the wording in the record.”

Years later, Mr. Ely explained his unusual vocal phrasing. He said that his braces had been tightened the day before recording. In addition, he had to stand on tiptoe to reach a microphone that an engineer had suspended from the ceiling to give a more ambient sound.

Members of the Portland-based band reportedly hated the recording. However, their manager pushed them to release it on a small local label. Sales were slow until Boston disc jockey Arnie “Woo-Woo” Ginsberg featured it as “the worst record of the week.”

Apparently, his listeners — in great numbers — disagreed. The record sold hundreds of thousands of copies despite competition from a similar version cut soon afterward by Paul Revere and the Raiders.

The Kingsmen split up not long after their sole hit. Drummer Lynn Easton wanted to sing and pushed Mr. Ely out of the band. Easton and Mr. Ely began operating rival groups under the Kingsmen name. Eventually, a lawsuit by Easton, whose mother had trademarked the Kingsmen, forced Mr. Ely to rename his outfit the Courtmen.

Mr. Ely was drafted into the Army and served in Germany at the height of the Vietnam War. His son said he struggled with heroin addiction after his return and eventually gave up full-time music to become a horse trainer. He released a gospel album, “Love Is All Around You Now,” in 2012.

Jack Brown Ely was born in Portland on Sept. 11, 1943. He learned piano as a child and turned to guitar after seeing Elvis Presley perform on television. He co-founded the Kingsmen in 1959.

His marriages to Kaaren Thompson and Dawn Packard ended in divorce.

Survivors include his third wife, Wendy Maxon Ely of Redmond; a son from his first marriage, Sean Ely of Portland; a daughter from his second marriage, Sierra Ely of Chattanooga; a son from a relationship, Robert Ely of Hono­lulu; a sister; two step-sisters; six grandchildren; and two great-grandchildren.

In 1998, the Kingsmen won a lawsuit for more than three decades’ worth of unpaid royalties. Mr. Ely later backed a movement to require radio stations to pay performance royalties — not just songwriting ones.

“It’s not just about me,” he told the Oregonian newspaper in 2009. “There are a lot of one-hit wonders out there just like me who deserve compensation when their recorded performances are played and stations get ad revenue from it.”

According to rock music historian Peter Blecha, advances in recording technology have revealed an actual obscenity on the Kingsmen’s recording of “Louie Louie.” About 54 seconds in, Blecha said, Easton uses a barely audible profanity after fumbling with a drumstick.