Reynolds had been hospitalized with acute respiratory disease and other illnesses, and died Wednesday in San Diego after his family took him off life support, said son Joshua Reynolds.
"Dad was so happy he turned people onto music in a way that people could really approach it, in a simple and honest way," Josh Reynolds told The Associated Press. "He was a very gracious and loving performer. He was a devoted family man."
The Kingston Trio's version of the 19th century folk song "Tom Dooley" landed the group a No. 1 spot on the charts in 1958, and launched the band's career.
Born on July 27, 1933, in San Diego, Nicholas Reynolds demonstrated an early love of music and did sing-alongs with his two sisters and their Navy captain-father, who taught him to play guitar.
He graduated from Coronado High School in 1951 and attended the University of Arizona and San Diego State University before attending Menlo College, a business school near Palo Alto. He graduated from Menlo in 1956.
It was during the mid-1950s that Nicholas Reynolds met Bob Shane, who introduced him to Stanford student Dave Guard. Guard and Shane knew each other from playing music in Guard's native Hawaii. The three formed the Kingston Trio.
In 1958, "Tom Dooley" earned Reynolds, Guard and Shane a trophy for best country and western performance at the first Grammys. The group, defined by tight harmonies and a clean-cut style, went on to win a Grammy the next year for best folk performance for its album "The Kingston Trio At Large."
Later member John Stewart joined the group in 1961, replacing Guard. Stewart died in January, also in San Diego.
After leaving the Kingston Trio in 1967, Reynolds moved to Oregon, where he stayed until the 1980s and took a break from music to raise his family, his son said.
Reynolds moved back to California in the mid-1980s and rejoined Stewart for one album. In 1991, Reynolds rejoined Shane in a reconstituted version of the Trio. He remained with the group until retiring in 2003, his son said.
Reynolds is survived by his wife Leslie, sons Joshua and John Pike Reynolds, daughters Annie Reynolds Moore and Jennifer Reynolds, and his two sisters.