In 1980, the band scored a slew of Hot 100 Billboard singles including "Freeze-Frame", "Love Stinks", and "Centerfold", and were staples on MTV.
"At approximately 4 p.m., Groton Police responded to a home on Graniteville Road for a well-being check", said the Groton Police in a statement.
The guitarist, whose group was best known for their 1982 hit Centrefold, was pronounced dead at his home in Groton, Massachusetts, on Tuesday.
Geils and the rest of the members of his band were nominated four times for induction into the Rock and Roll Hall of Fame, although they never made it in.
Centrefold, their biggest hit, topped the United States charts for six weeks in 1982 and reached number three in the UK.
Withdrew to Groton, J. Geils, who continued to play occasionally jazz and blues, had then discovered a passion for the restoration of race cars, according to AutoWeek.
"Freeze-Frame" (from Freeze-Frame, 1981) - Wolf and Justman brought the band into the top ten with this song, which reached #4, and helped bring the band to a larger audience.
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The group would reunite repeatedly over the years, but in 2012, Geils chose to leave for good. It has since periodically reunited, once to perform at the opening concert for the new House of Blues in Boston in 2009 and another time as the opening act for Aerosmith at Fenway Park the next year.
"All our love and sympathy to the family and friends of John Warren Geils Jr.", Van Zandt wrote on Twitter.
Born in NY in 1946 and raised in New Jersey, Geils was best known as a musician, but his first love was cars - a passion he inherited from his father along with his ear for music, he told Autoweek in 2012.
In 1999 the band would play the occasional reunion shows, but in 2012 Geils officially quit the group and sued his bandmates for plotting a tour without him - using his band's trademarked name.
Wolf paid tribute to Geils following the news of his death on Tuesday night.
Geils once again took up the guitar in 1992, joining Magic Dick in the group Bluestime.