Steve Harwell, the longstanding leader of the pop rock band Smash Mouth, who had been nominated for a Grammy, has passed away at the age of 56.

Robert Hayes, the manager of the band, stated that Harwell "passed peacefully and comfortably" on Monday morning at his home in Boise, Idaho, surrounded by family and friends, according to a report by The Associated Press.

According to the statement, the cause of death was acute liver failure.

The band Smash Mouth achieved mainstream success with songs like "All star" and "Then the morning comes."

“Steve Harwell was a true American Original. A larger than life character who shot up into the sky like a Roman candle,” Hayes said. “Steve should be remembered for his unwavering focus and impassioned determination to reach the heights of pop stardom.”

Harwell, who was born in California in 1967, performed with the rap group F.O.S. (Freedom of Speech) prior to establishing Smash Mouth in 1994.

The band released two platinum albums on Interscope Records, the ska-infused "Fush Yu Mang" and "Astro Lounge" in 1998 and 1999, respectively.

The second album featured some of the band's greatest hits, including the platinum-certified, Grammy-nominated single "All Star," which appeared in the film "Shrek" alongside their rendition of the Monkees' "I'm a Believer."

Smash Mouth's success was driven largely by humor, with Harwell's lively alt-rock voice and persona at the forefront. He made a cameo appearance in the 2001 comedy film "Rat Race," and had a well-known friendship with Food Network chef and presenter Guy Fieri.

“His only tools were his irrepressible charm and charisma, his fearlessly reckless ambition, and his king-size cajones,” Hayes said. “Steve lived a 100% full-throttle life. Burning brightly across the universe before burning out.”

“He will be greatly missed by those who knew and loved him,” he said.

Harwell left Smash Mouth in 2021, after which the band proceeded to tour with singer Zach Goode.

The band released a statement at the time indicating that Harwell had been diagnosed with cardiomyopathy eight years prior and had endured “nonstop serious medical setbacks including heart failure as well as acute Wernicke Encephalopathy.”

Hayes had issued a statement on Sunday indicating that Harwell was receiving treatment from a hospice facility.

According to Hayes, Harwell will have his body cremated in Boise, and then his remains will be interred next to those of his mother in San Jose, California.