|Plot details follow, read at your own risk.|
- "What happened is that someone took a shot at my bus and then cops turn up and start treating me like I'm some sort of pachuco punk. My people have been in California for over three hundred years."
- ―Felix Alvarro
Alvarro worked as a bus driver in Santa Cruz, Los Angeles. He enlisted in the United States Marine Corps, and was assigned to the Sixth Marines and fought in Okinawa and Peleliu, alongside Lieutenant Cole Phelps and Sergeant Jack Kelso as a rifleman.
On their way home from the war, Alvarro and his fellow Marines were shipped on board the SS Coolridge. They reflected on their unsatisfactory jobs to return home to, prompting Courtney Sheldon to convince a number of Marines into stealing the cargo of army surplus morphine - with the intent to sell on the streets. With the exception of Kelso, they committed the theft, stealing half a million syrettes. Upon returning to Los Angeles, Sheldon established a business arrangement with the Cohen Crime Syndicate, in order to sell the morphine to abortion clinics and hospitals. Alvarro resumed his job as a driver for Interstate Bus in Los Angeles.
Events of L.A. Noire
- "It's a tough break to go through Okinawa and then have to buy it back home."
- ―Felix Alvarro
However, there was a feud between Mickey Cohen and Sheldon. Cohen started into selling the morphine to the addicted, gaining a considerable advantage on the cities drug trade, since the morphine required no preparation. Sheldon, realizing this, pulled out of the deal with Cohen. Sheldon and Kelso arranged a meeting, with Alvarro holding the meeting in enfilade. Cohen later retaliated by ordering the assassinations of the Marines involved in the SS Coolridge Heist.
A sniper was hired to kill Alvarro, intercepting his bus while on the roof of building. The sniper opened fire against Alvarro and the bus with a BAR, but was saved by the intervention of the LAPD, the sniper was killed by Detective Phelps. Phelps questioned Alvarro due to his suspicions of Alvarro's involvement in the morphine robbery and distribution. Phelps coerced Alvarro into revealing a link between Sheldon and Cohen.
Alvarro later agreed to attack the mansion of Leland Monroe at Kelso's request. Jack Kelso, Patrick Connolly, another ex-Marine and Alvarro met along the perimeter and formed their attack plan. Afterwards, they stormed the courtyard, killing a number of Monroe's guards, before reaching the house. Once there, Kelso ordered Alvarro and the others to maintain the perimeter and guard the house. Kelso entered the mansion to personally deal with Monroe.
- The player can unlock the Achievement/Trophy The Fighting Sixth by getting Alvarro to give up the Marines involved in the SS Coolridge heist.
- Felix Alvarro's actor, Manny Montana, also shares his face with Juan Garcia Cruz in Reefer Madness.