San Jose music icon Steve Harwell of the band Smash Mouth dies at 56.

Steve Harwell, the singer who took one of the most popular San Jose rock bands of all time — Smash Mouth — to great heights in the late ‘90s and early 2000s, died Monday at the age of 56.

“Steve Harwell was a true American original,” the band posted Monday on X (formerly known as Twitter). “A larger than life character who shot up into the sky like a Roman candle. Steve will be remembered for his unwavering focus and impassioned determination to reach the heights of pop stardom.

“Rest in peace knowing you aimed for the stars, and magically hit your target,” the band’s statement said. “Rest easy.”

Harwell died from liver failure at his home in Boise, Idaho, the band’s manager, Robert Hayes, confirmed to the New York Times. He had been receiving hospice care for several days from his fiancée Annette Jones.

Harwell will be remembered as the charismatic, full-throttle singer whose rowdy, upbeat voice powered the Smash Mouth hits “Walkin’ on the Sun,” “I’m a Believer” and, especially, “All Star.”

Originally released on Smash Mouth’s sophomore album, 1999’s “Astro Lounge,” the entirely catchy “All Star” was quickly utilized in a number of different films, including “Inspector Gadget” and “Mystery Men” — the latter of which played into the band’s music video for the song.

The song hit No. 1 on the Billboard Mainstream Top 40 chart and wound up being nominated for a Grammy.

Yet, it would grow even more popular two years later when it was memorably featured in the opening credits of the 2001 DreamWorks animated smash “Shrek.”

Smash Mouth basically ended up opening and closing the film, as the San Jose band’s cover of “I’m a Believer” — the Neil Diamond-penned Monkees hit from 1966 — was chosen for the closing scene of the film.

The massive success of “Shrek” — which ranked only second to “Harry Potter and the Sorcerer’s Stone” among the top-grossing films in the U.S. in 2001 — greatly expanded Smash Mouth’s fan base, especially among younger listeners.

Yet, it wasn’t just a temporary occurrence, but, really, something that has continued to this day as new generations of viewers journey into the magical world of Shrek, Donkey and Fiona.

People who grew up during the time of “Shrek” will likely remember these Smash Mouth songs as fondly as earlier generations recall such Disney tunes as “Someday My Prince Will Come” and even “When You Wish Upon a Star.”

Steven Scott Harwell was born in January 1967, and grew up in San Jose. He cofounded the band — which originally went by Smashmouth — in 1994 in San Jose with drummer Kevin Coleman, guitarist Greg Camp and bassist Paul De Lisle. Prior to that, Harwell was a rapper in a group called F.O.S. (Freedom of Speech).

The band’s first big break came when the legendary San Jose radio station KOME played a demo of the song “Nervous in the Alley,” which helped it garner publicity and paved the way to its signing by mighty Interscope Records.

The full-length debut album “Fush Yu Mang” came out in 1997 and introduced fans to the band’s commercial friendly mix of ska, retro surf rock, big pop hooks and frat-house fun. The album went on to sell over 2 million copies, propelled — one might say almost entirely — by the career-making single “Walkin’ on the Sun.”

Smash Mouth’s next album, “Astro Lounge,” was even bigger, reaching triple-platinum heights on the back of “All Star.”

The good times would last for one more full-length, as the band managed to eek out gold status with 2001’s self-titled affair. Yet, musical tastes were changing by that point, with Smash Mouth’s increasingly homogenic brand of ’90s-rooted alt-rock losing favor with the public.

The group’s next major label release — 2003’s weak-selling “Get the Picture?” — turned out to be its last, although Smash Mouth would put out three more independent albums with Harwell on the microphone, the last of which was 2012’s “Magic.”

As Smash Mouth’s fortunes declined, Harwell became an increasingly unstable presence onstage. In 2016, he reportedly collapsed during a concert in Illinois and was rushed to the hospital, while the rest of the group finished the show without him.

The low point came in October 2021, during a now-infamous Smash Mouth show at The Big Sip festival near Syracuse, New York. A video of the show was posted on TikTok — and quickly viewed over 1½ million times, causing Harwell and the band to trend on social media for all the wrong reasons.

The video shows Harwell slurring his words, swearing at the crowd and issuing a harsh threat to someone, saying “I’ll (expletive) kill your whole family, I swear to God.”

He also makes a gesture with with his arm that the Los Angeles Times described as “what appeared to be a Nazi salute to the crowd.”

“When I say that this is the most chaotic show I have ever seen in my life … I have no words,” says the concert attendee at the start of the video.

Following the outcry over the performance, Harwell announced his retirement from the band in order to focus on mental health issues.

“Steve has been dealing with long-term medical issues over the last eight years and during his last performance at The Big Sip stage, he suffered numerous symptoms directly linked with his current medical situation,” a rep for Harwell told the New York Post at the time. “As of today, Steve will be retiring from Smash Mouth to focus on his physical and mental health.”

The New York Post identified the medical condition as cardiomyopathy, which can led to heart failure. Harwell also reportedly suffered from Wernicke’s encephalopathy, a neurological condition that can cause imbalance, confusion, memory loss and speech impairment, and for years battled alcohol abuse.

Harwell also endured a great amount of tragedy over the years. Notably, in July 2001 — while Smash Mouth was at the height of its career — his son Presley died in from acute lymphocytic leukemia at the age of 6 months. The singer would then go on to honor the memory of his son by establishing a medical research fund in Presley’s name.

Smash Mouth continues to perform with Zach Goode handling the vocals.

According to the New York Times, he is survived by Jones, his fiancée; a brother, Mark, and three sisters, Carla Crocker, Michelle Baroni and Julie Harwell. There was no word Monday of any services planned.