When he signed up to serve as an infantryman in Vietnam in 1966, Jim Johnson left behind what many considered the best rock band in Minneapolis at the time, the Underbeats. Then when he returned from war, he left Minnesota behind for Los Angeles, where his group evolved into Gypsy, served as a house band at the famed Whisky a Go Go and recorded for RCA Records.

Perhaps because of his two years of war duty in between those musical runs, the fact that national fame remained elusive apparently never became too much of a disappointment for Johnson, who died Thursday of esophageal cancer. He was 76.

“After Vietnam, he just sort of went with the flow and was happy to just be playing music,” said Johnson’s longtime bandmate and childhood friend Doni Larson. “The guy was born a musician. It was in his blood.”

Also known by the stage name Calvin James — a flip on his first and middle names — Johnson racked up many random bits of fame outside Minnesota over the years.

Both Ray Charles and Guitar Slim recorded his song “Too Hard to Love You.” The Fifth Dimension cut two of his tunes for its 1975 album “Earthbound.” Gypsy themselves became radio sensations in St. Louis and a few other markets, unbeknown to the band members at the time.

Most of his success, though, came in Minnesota and the Upper Midwest, a fact underlined in 2016 when Johnson became the inaugural recipient of the Bill Diehl Award, named after the WDGY disc jockey and promoter who godfathered that era’s garage-rock bands such as the Underbeats, the Accents and the Trashmen.

“The Underbeats were probably the best band that came out of Minneapolis in the ’60s,” Trashmen guitarist Tony Andreason told author Rick Shefchik for his tome “Everybody’s Heard About the Bird: The True Story of 1960s Rock ’n’ Roll in Minnesota.”

With Johnson leading the charge on guitar and often vocals, the Underbeats scored one of the biggest regional hits of the early 1960s with “Foot Stompin’,” issued in 1964 by Nic-o-Lake Record Store operator George Garrett’s namesake label. Garrett also first recorded the Trashmen’s “Surfin’ Bird.”

“It was a novelty tune,” Larson recalled. “We did it because all the kids liked to stomp their feet at shows. It was as simple as that.”

All that stomping led to a legendary tale about fans dancing so excitedly to the Underbeats that the floor partly caved in at Big Reggie Colihan’s Danceland Ballroom in Excelsior, where the Rolling Stones and Beach Boys also famously played in the mid-’60s.

By the time Johnson left for Vietnam — after two other members of the band were drafted — Underbeats drummer Rod Eaton remembers them often performing six nights a week everywhere from dance halls in rural towns to the Duluth Armory to teen clubs such as Mr. Lucky’s in Minneapolis.

“You could really make a living as a working musician in those days, so we really were having the time of our life,” Eaton said.

As the lineup, band name and style of music all changed into the more psychedelic-sounding and jammy Gypsy in 1968, the group signed up with the Guess Who’s management team, kept up its Whisky gig for nearly a year and then recorded its self-titled 1970 debut album, which included the single “Gypsy Queen.” After three more poorly promoted albums, though, Gypsy split up by 1975.

“It was just bad management after bad management,” Larson complained.

Through it all, Eaton and Larson agreed, Johnson often served as the driving force who urged his bandmates to rehearse on a nearly daily basis. “He was the taskmaster, in a good way,” Eaton said.

A native of Waterloo, Iowa, Johnson learned to play guitar after moving to northeast Minneapolis around age 12, where he attended Edison High. He became especially adept at copying Chuck Berry licks but also had a feel for country, surf-rock and blues styles of playing.

After moving back to Minneapolis from Los Angeles in 1993, he also returned to gigging around town. He launched a revamped version of the Underbeats, played occasional reunion shows by Gypsy and explored more blues and R&B territory with Calvin James & Bad Influence, which also featured Larson.

“The pay is about the same in clubs today” as it was back in the ’60s, Johnson half-joked to the Star Tribune in 2004, when the Underbeats were among the inaugural class of acts inducted into the Minnesota Rock & Country Hall of Fame. Still, his love for his bands shined through.

“It’s nice to hang out with old friends and to get a piece of paper to hang on the wall,” he said of the occasion.

Johnson is survived by daughter Lisa and two grandchildren. Memorial plans are pending.