Pike died June 9 at his home in Prescott, Arizona, his sister-in-law Becky Pike told The Associated Press on Wednesday. The cause was complications of Parkinson's Disease.
Pike and Bob Engemann, a college buddy from Brigham Young University, formed The Lettermen in Los Angeles in 1961 with fellow singer Tony Butala.
They were looking for a name that would resonate with young people, Pike's younger brother, Gary, said Wednesday, when Engemann suggested The Lettermen. Butala noted that he'd briefly sung with a group using that name and he'd have to ask its leader for permission.
"Tony called him up and he said he wasn't using it, so they said, 'Yay. We're going to use it," Gary Pike recalled with a laugh.
Later that year the group had its first hit with the Grammy-nominated "The Way You Look Tonight," which peaked at No. 13 on Billboard's Hot 100.
The Lettermen would place 19 more songs on Billboard charts over the next 10 years.
Two made the Top 10, 1962's "When I Fall in Love" and the Grammy-nominated 1968 medley "Goin' Out of My Head/Can't Take My Eyes Off Of You." Their last hit was 1971's "Everything is Good About You."
The Lettermen also earned Grammy nominations for best new artist of 1961 and for 1962's "A Song For Young Love."
Through those years the group toured constantly, playing colleges across the country and other venues around the world.
The constant touring wore out Pike's voice and he left the group in 1973, replaced by his youngest brother, Donny Pike. Gary Pike had replaced Engemann in 1967.
After regaining his voice Pike formed a group called The Reunion with Engemann.
The Lettermen, with Butala as the only remaining founding member, continues to tour. Engemann died in 2013.
In addition to his brothers, Pike is survived by his sister, Candace Doyle, his wife Sue and his daughter, Kelly Pike.