Layne was born on August 22, 1967 in Kirkland Washington, His parents were divorced by the time Layne was eight and this devestated him, Soon after his family recieved a phone call call that his father was dead, making Layne's sadness worse, but it later turned out to be false. Layne describes his experience from an Adriana Rubio Interview: "My world became a nightmare," he said. "There were just shadows around me. I got [a] call saying that my dad had died, [but] my family always knew he was around doing all kind of drugs. Since that call I always was wondering, 'Where is my dad?' I felt so sad for him and I missed him. He dropped out of my life for fifteen years." Staley then discovered that he had talent to become a rockstar, thinking that if became a celebrity his dad would return. So he started writing songs in his teens and jamming with other musicians. At the same time, he did a bit of research to find out where his father was living and what kind of a man he was.

At the age of twelve, Staley began playing drums and played in several glam bands in his early teens, but aspired to be a singer. Whenever he told this to his fellow bandmates, they often poked fun of him, this infuriated Layne so much. He later traded in his drum set for a microphone. He met up with Jerry Cantrell in 1987 while at a party, Jerry then introduced Layne to the other members( Sean Kinney and Mike Starr) and joined Cantrell's band Diamond Lie. Eventually, the band renamed itself Alice in Chains. Originally a glam band, Alice in Chains shifted into marked metal influences, and was soon included as part of the burgeoning grunge movement.

Like several other musicians in the Seattle grunge scene, Staley experimented with heroin. By the 1990s, Staley was battling an addiction. The darker side of addiction had its influence on Staley's lyrics. The Alice in Chains album Dirt showed this preoccupation in songs like "Sickman" and "Dirt", while Cantrell's lyrics focused mainly on the thoughts of death. "Would?" in particular addresses the death of Andrew Wood, singer of Mother Love Bone, who died of a heroin overdose in 1990.

Alice in Chains opted not to tour in support of their 1994 EP Jar of Flies. Following its release, Staley began to work on a side project with several Seattle musicians, including Mike McCready of Pearl Jam and Mark Lanegan of the Screaming Trees. The band worked on material for several months, and eventually scheduled a show at the Crocodile Cafe under the name The Gacy Bunch. Within a few weeks, the band changed its name to Mad Season. In January of 1995, Mad Season performed two songs on Pearl Jam's Self Pollution Radio broadcast, "Lifeless Dead" and "I Don't Know Anything". The band completed an album, titled Above, which was released in March of 1995. The first single, "River of Deceit", became a modest success at alternative radio. A live performance filmed at the Moore Theater in Seattle was released in August of 1995.

During Alice in Chains' hiatus, rumors of Staley's heroin addiction began to spread. Alice in Chains regrouped to record a self-titled album, released late in 1995. To accompany the album, the band released a home video, The Nona Tapes, in which they poked fun at the rumors of Staley's addiction – several sources had announced his death during the hiatus, Charles Cross would later say that they had Staley's obituary on stand-by at The Rocket – but the band lapsed again, failing to complete tours planned in support of the album. After the death of his girlfriend, Demri Parrott, in 1996 from bacterial endocarditis caused by drug use, Staley became more and more reclusive. Fans saw firsthand the effects of Staley's drug abuse during the band's Unplugged appearance. Staley was visibly weak and emaciated and had problems singing at times. His last performance was on 3 July 1996 in Kansas City, Missouri, while they were touring with KISS after their Unplugged appearance.

Staley remained out of the spotlight for the next several years. In 1998, Staley emerged as part of a supergroup called Class of '99, featuring members of Rage Against the Machine and Porno for Pyros. The group recorded parts one and two of Pink Floyd's "Another Brick in the Wall" for the soundtrack to the movie The Faculty, with a music video filmed for part two. While the other members of the group were filmed specifically for the video, Staley's appearance consisted of footage pulled from Mad Season's 1995 Moore Theater video.

In October of 1998, Staley emerged to help record two new tracks ("Get Born Again" and "Died") with Alice in Chains, which were released on the Music Bank box set in 1999. On July 19, 1999, syndicated radio program Rockline was hosting Cantrell, Inez, and (via telephone) Kinney for a discussion on the release of Nothing Safe: Best of the Box, when, unexpectedly, Staley called in to participate in the discussion.

At the beginning of 2002, Staley conducted an interview with author Adriana Rubio, in which Staley talked about the damage caused by his heroin addiction: "I'm not using drugs to get high like many people think. I know I made a big mistake when I started using this shit. It's a very difficult thing to explain. My liver is not functioning and I'm throwing up all the time and shitting my pants. The pain is more than you can handle. It's the worst pain in the world. Dope sick hurts the entire body."

On April 19, 2002, Staley was found dead in his home. His body was surrounded by various drug possessions and equipment. He was thirty-four years old. As he had apparently died two weeks earlier, Staley's body was not immediately identifiable, and a positive identification was not released until the next day. The autopsy report later concluded that Staley died after injecting a mixture of heroin and cocaine known as a "speedball". By coincidence, the coroner's office estimated that he died on April 5, the same date that fellow Seattle Grunge rocker Kurt Cobain was estimated to have died eight years earlier.

Friend and bandmate Jerry Cantrell, who had tried to stay in touch with Staley and maintain their friendship, released the solo album Degradation Trip in June 2002 and dedicated the album to Staley's memory.

Several other musicians paid tribute to Staley in music. Aaron Lewis, lead singer of Staind, penned a tribute to Staley titled "Layne" for Staind's 2003 album 14 Shades of Grey. Eddie Vedder, lead singer of Pearl Jam, also recorded a song eulogizing Staley, titled "4/20/02" (the day Vedder heard the news and subsequently wrote the song). The song featured only Vedder singing and playing the guitar in a ukulele-inspired tuning, and was released as a hidden track on Pearl Jam's 2003 B-sides album Lost Dogs. Zakk Wylde also wrote a song about Layne Staley called "Layne" on the Black Label Society album, Hangover Music Vol. VI.

Following Staley's death, Alice in Chains officially disbanded. For the next several years, the band refused to perform together out of respect for Staley. In 2005, the remaining members reunited for a benefit concert for victims of the 26 December 2004 tsunami, with several vocalists filling in for Staley. Following positive response, the band decided to reunite formally in 2006. In an interview with MTV News, Alice in Chains drummer Sean Kinney noted that the band would use the reunion concerts to pay tribute to the songs and to Staley. William Duvall, a member of Cantrell's solo touring band (who often sang Staley's parts on the Alice in Chains songs that Cantrell performed), was announced as Staley's replacement for the reunion shows.

In the same interview, Kinney noted the reunion didn't necessarily foretell a future for Alice in Chains. "If we found some other dude, I'd love to move on, write some cool tunes and change the name and go on like that. I don't see continuing as Alice and replacing somebody. ... We're not trying to replace Layne. We want to play these songs one more time, and if it seems like the right thing to do, it'll happen. I don't know how long it will go or where it will take us. It's kind of a tribute to Layne and our fans, the people who love these songs."

In 2003, Layne's mother Nancy McCallum and Jamie Richards, a drug and alcohol counselor, formed the Layne Staley Fund, a non-profit organization that raises money for drug treatment and works with the Seattle music community. A yearly tribute is held in August, on or around Layne's birthday, to celebrate his music and to spread a message of hope to prevent further tragedy. The federal non-profit number of this charity is 20-168-2910.