Elwood is a member of the inbred redneck O'Neil family, and brother to several siblings, including Walton, Wynn, Ernie, Earl, Dale, Doyle, Daryl and Dan. The family was raised in a ranch in Grapeseed, Blaine County, San Andreas, which they still use as a home and meth lab. The brothers are involved in selling drugs and cooking meth, with Elwood serving as a leader to his brothers.
Events of Grand Theft Auto V
Rivalry with Trevor
The Los Santos Triads, who seek to expand their business in Blaine County, choose to partner with the O'Neil brothers instead of Trevor due to the latter's violent and reckless behaviour, beating Trevor to the agreement. After forcing Tao Cheng's translator to reveal that they're now working with the O'Neils, an enraged Trevor decides to destroy the O'Neil Ranch as retribution for stealing his potential clients and ruining his dream of becoming an "international drug dealer and weapons trader". On the way to the farm, Trevor calls Elwood, who tells him it was business and Trevor can come to discuss the partnership at the farm, where all of the O'Neils are at the moment.
But Trevor violently dismisses the offer and tells Elwood of his intentions to attack the farm.
Fearing of Trevor's attack, Elwood informs his brothers of the psychotic drug dealer's arrival and tells his family to protect the meth lab from Trevor at all costs, after which he drives away with his brothers Walton and Wynn to meet up with the Cheng family.
However, despite their best efforts, all of the brothers (except for Elwood, Walton and Wynn) are slaughtered by Trevor, who finishes his rampage against them by pouring gasoline in-and-outside the lab before blowing up the farm, destroying their home and meth lab.
Quest for vengeance
Elwood and his two brothers eventually returned to the farm, only to discover it has been destroyed and their brothers dead. An enraged Elwood phoned Trevor, who is in Los Santos and threatened to kill him. Trevor, however brushed away the threat and gave away his location, while taunting Elwood and daring him and his brothers to come to Los Santos and kill him. Elwood, Walton and Wynn then traveled with Elwood's Dubsta to Los Santos. After discovering where Trevor is being holed up, the O'Neils were going to fire anti-tank rockets at Trevor's safehouse only to learn from one of Trevor's roommates that Trevor has returned to Sandy Shores.
Still determined to kill Trevor and avenge their fallen brothers, Elwood, Walton and Wynn travel back to Sandy Shores to find Trevor, all while not knowing that they were being tailed by Trevor's associate Franklin Clinton on Trevor's request, who wishes to take out the remaining O'Neils, so that Trevor could exact his full revenge at the O'Neils for stealing his earlier business contract with Wei Cheng as well as putting an end to their seeks for vengeance. The O'Neils discover that Franklin is tailing them and attempt to escape from him, but an elk on the road leads to their crash and subsequent escape into a forest, located somewhere in the Raton Canyon. Unable to find the O'Neils in the forest by himself, Franklin calls Trevor for air support. Trevor and his other associate Michael De Santa come with a helicopter to help Franklin with the O'Neils.
Using a rifle, fitted with a thermal scope, Michael shoots Walton and Wynn dead, but can't get a clear image of Elwood, who is hiding behind a rock and suddenly starts firing anti-tank rockets at the helicopter. With the help of Chop, Franklin locates Elwood and shoots him while he tries to escape, killing him.
Grand Theft Auto V
- Elwood can be killed either by Franklin or Michael. When Franklin is chasing Elwood, the player can switch back to Michael and snipe Elwood from the helicopter.
- In Grand Theft Auto Online, Franklin will mention Elwood O'Neil's death to the GTA Online Protagonist about Chop, saying that "Chop don't fuck around. He got bodies. Hey, just ask Elwood O'Neil".