Born as the son of Valerio Marcano, a low-level and disgraced member of the Carillo Crime Family, Lucio lived with his father and brothers in a shed in River Row and was arrested along with his brothers Sal and Lou at a Louisiana State Penitentiary at Cordoba for a series of robberies and crimes around New Bordeaux, while their youngest brother Tommy was in elementary school.
In 1934, Sal had his own father killed and blamed Giuseppe Carillo for the hit, convincing Lucio, Lou and their underlings to declare war on Carillo. That same year, while Carillo was dining at a popular Italian restaurant in the French Ward, the Marcano brothers and their crew ambushed Carillo and shot the place up, killing Giuseppe Carillo and 18 of his men and guests.
After Carillo's murder, the Marcano family took over New Bordeaux. After the takeover, Lucio started helping Lou organizing their Prostitution rackets around the city, building up some high-class and rich clientele in Frisco Fields. In the process, he ended up meeting and dating Olivia Grady, a young rich woman, and despite her parents despising Lucio due to him being a pimp and a pusher, he married her in 1949.
After that, Lucio got Olivia involved in the Marcano family businesses, and would often take her with him to businesses involving fast cars, automatic weapons, as well as recreational drug use. However, in 1962, Lucio was found dead with his throat slit, allegedly by one of his prostitutes. However, it is said that Olivia hired some men to kill her husband so she could take over his operations, and John Donovan personally believes this to be true.
- Olivia Marcano (wife, deceased)
- Sal Marcano (brother, deceased)
- Lou Marcano (brother, deceased)
- Tommy Marcano (brother, deceased)
- Giorgi Marcano (nephew, deceased)
- Michael Grecco (nephew, deceased)
- Virginia Marcano (sister-in-law, deceased)
- Valerio Marcano (father, deceased)
- Sal Marcano stated that he had nightmares a month after Lucio died, suggesting that the two were close.
- Olivia Marcano described that when she first met Lucio, he was dashing and handsome, and only drove the fastest cars and wore the finest suits.
- Lucio is the only Marcano brother who wasn't killed by Lincoln Clay and also the only one not to make a physical appearance in the game. It is unknown if he met or even knew of Lincoln Clay when he was alive.