with friends he met while attending the Finnish Pop & Jazz Conservatory,[4] Laiho formed Children of Bodom together with drummer Jaska Raatikainen, under the name of IneartheD.

[5][6] On 31 October 1997, prior to releasing their debut album, Children of Bodom played their first concert in Helsinki, as opening act for Norway's Dimmu Borgir.

"There was this fucking beast on the guitar," added Dimmu's then-keyboardist Kimberly Goss, who formed power metal band Sinergy with Alexi in 1997, and married him in 2002.

An unreleased fourth album was recorded and slated to be released in 2005,[8] but the finishing touches were never completed due to Laiho's demanding schedule with Children of Bodom.

In 2004, Laiho founded a side-project called Kylähullut, which was assembled together with drummer Tonmi Lillman (ex-Sinergy) and singer Vesa Jokinen 69er of Finnish punk band Klamydia.

On 3 July 2012, Children of Bodom announced on their Facebook page that they had to cancel two European shows because Laiho had been taken to the hospital because of severe stomach pain.

Laiho died on 29 December 2020 due to liver degeneration resulting from years of alcohol abuse,[16] leaving behind a few songs recorded with Bodom After Midnight to be published posthumously.

[28] On 1 February 2002, at a private ceremony in Finland, Laiho married long time girlfriend and Sinergy frontwoman Kimberly Goss.

[30] The couple separated in 2004, but were on good terms and had regular text and video contact until the day he died, as confirmed by the Finnish press.

[31] Drama and infighting between Laiho's sister and widow resulted in a public back and forth exchange, with both parties airing their grievances to the Finnish media.

"[21] In 2024, Janne Wirman revealed that after Alexi's return from Australia, where he had spent time with his partner, Kelli Wright, his bandmates started noticing that Laiho's health was deteriorating.

[41] On 5 March 2021 Kimberly Goss revealed the official cause of Laiho's death on her Instagram: "alcohol-induced degeneration of the liver and pancreas connective tissue".

The cause of death was originally published in Finnish as "maksan rasvarappeutuminen ja haiman sidekudostuminen", which translates into English as fatty liver disease and pancreatic fibrosis.

[42] Laiho's sister stated that the family wanted the details of his death to remain private,[31] however Goss maintained that it was her right as his legal widow to disclose the information and bring closure to his fans, hoping the tragedy could inspire lives to be saved and "help others struggling with these same demons.