Steve Harwell, the previous lead singer of the rock band Smash Mouth, which was finest identified for its 1999 hit “All Star,” died on Monday. He was 56.

His demise, at his house in Boise, Idaho, was confirmed by the band’s supervisor, Robert Hayes, who stated the trigger was liver failure.

Smash Mouth was based in 1994 in San Jose, Calif., and was made up of Mr. Harwell, the guitarist Greg Camp, the drummer Kevin Coleman and the bassist Paul De Lisle. Its first success got here with the music “Walkin’ on the Sun,” from the band’s debut album, “Fush Yu Mang” (1997).

An upbeat observe with a darkish undertow, calling to thoughts each the Doorways and up to date ska-punk, “Walkin’ on the Solar,” with songwriting credit going to all 4 band members, went into regular rotation on MTV and topped Billboard’s different chart.

The music’s music video laid out the band’s aesthetic and perspective. Wearing short-sleeve shirts and shades, with fedoras and soul patches, the 4 members seemed like rougher variations of the image-obsessed retro hipsters depicted within the 1996 comedy “Swingers.” The video contains a dance celebration straight out of a Sixties seashore film and ends with a drag-race crash, with Mr. Harwell — beefy, with tattoos on his arms — behind the wheel.

“The query of a specific fashion by no means as soon as crossed our minds,” Mr. Harwell stated in a 1997 interview. “We didn’t need to be labeled as a punk band, a ska band, a surf band, a rock band, a pop band or a no matter band. We simply wished to be us, Smash Mouth, and depart it to the folks to interpret what we’re.”

The band’s big-time crossover got here with “All Star,” from its subsequent album, “Astro Lounge,” in 1999. Backed by harder-driving guitars, Mr. Harwell, with a slight sneer, sings an outsiders’ anthem to disregard ridicule and shoot for the moon:

Hey now, you’re an all star
Get your sport on, go play
Hey now, you’re a rock star
Get the present on, receives a commission

“All Star” — written by Mr. Camp, the band’s guitarist — went to No. 4 on Billboard’s Scorching 100 singles chart, the band’s best-ever chart place, and located a long-lasting viewers by way of film soundtracks. In 1999, it was utilized in “Inspector Gadget” and “Thriller Males,” and two years later the music received its broadest publicity when it performed through the opening credit of “Shrek,” the animated hit that featured Mike Myers as a grouchy however good-hearted ogre.

The “Shrek” soundtrack — which additionally featured Smash Mouth’s amped-up model of the Monkees’ “I’m a Believer,” within the closing scene — went double platinum, and the movie received an Academy Award for finest animated characteristic. “All Star” was all over the place.

“We had no clue how huge ‘Shrek’ was going to be,” Mr. Harwell recalled in a 2019 article in Rolling Stone. “We bought thousands and thousands of data off that alone. The music was reborn once more.”

Since then, “All Star” has lived on, changing into a rich source for online parodies. Practically 25 years later, the music has garnered practically a billion streams on Spotify alone, and the sound of Mr. Harwell’s barely raspy voice remains to be linked to the music’s recognizable opening traces: “Any person as soon as instructed me/The world is gonna roll me/I ain’t the sharpest software within the shed.”

Steven Scott Harwell was born on Jan. 9, 1967, and grew up in San Jose. He started his musical profession as a rapper with the group F.O.S., which stood for Freedom of Speech. With a sound harking back to West Coast teams of the late Eighties and early ’90s like N.W.A and Cypress Hill, it launched a single, “Large Black Boots,” in 1993. However by then Mr. Harwell was already stressed.

“Across the time we had been about to place out our single, this child Snoop Dogg got here out and adjusted every little thing,” he recalled in 2017 interview with the music web site Stereogum. “I used to be at a radio conference in Las Vegas watching MC Hammer, of all folks, and I simply checked out my supervisor, ‘I’m uninterested in all this hip-hop’” — he added an expletive — “‘I need to begin another rock band.’”

After “Astro Lounge,” Smash Mouth launched 5 extra studio albums by way of 2012, with diminishing ranges of success. In 2006, Mr. Harwell was a forged member on “The Surreal Life,” a actuality present on VH1 wherein onetime celebrities dwell collectively; his fellow forged members included Sherman Hemsley of “The Jeffersons,” Florence Henderson of “The Brady Bunch” and Tawny Kitaen, identified for her appearances in Whitesnake music movies.

For the final decade, Mr. Harwell’s profession had been marked by well being issues and sometimes erratic habits. In 2013, he was recognized with cardiomyopathy, a coronary heart situation, and Wernicke’s encephalopathy, a neurological situation that may have an effect on speech and reminiscence.

In August 2020, whereas many components of the nation had been nonetheless below main restrictions associated to the Covid-19 pandemic, Smash Mouth appeared on the Sturgis Motorcycle Rally, an enormous annual occasion in South Dakota, and carried out earlier than 1000’s of followers — only a few of whom, based on experiences and movies of the occasion, had been carrying masks or taking any precautions.

Mr. Harwell drew cheers from the group — however large condemnation elsewhere — when he stated from the stage, “We’re all right here collectively tonight, and we’re being human as soon as once more,” and made a crude dismissal of the viral risk.

In 2021, Mr. Harwell left the band and retired from performing after a dwell present in upstate New York during which he was seen slurring his phrases, utilizing profanity and apparently giving a Nazi salute.

“I’ve tried so onerous to energy by way of my bodily and psychological well being points, and to play in entrance of you one final time, however I simply wasn’t in a position to,” he stated in a press release on the time.

He’s survived by his fiancée, Annette Jones; a brother, Mark; and three sisters, Carla Crocker, Michelle Baroni and Julie Harwell.

In 2022, Smash Mouth recruited a brand new lead singer, Zach Goode, and the group has live shows scheduled in coming weeks, together with one on Thursday in Madera, Calif. Mr. Hayes, the supervisor, stated the band was nonetheless scheduled to carry out there.

In a press release on Monday, Mr. Goode stated: “I really like singing these songs each night time and carrying on the spirit of rock n roll in entrance of one of the best followers on the earth. I’ll proceed to strive, in my very own method, to honor what Steve and the band have created.”