The shooting happened on June 19, 2021 during Chicago's Puerto Rican festivities in the Humboldt Park neighborhood
Anthony Lorenzi was found guilty on six counts of second degree murder on Thursday. He was arrested in San Diego, California weeks after the shooting.
Yasmin Perez, 25, and the father of her children, Gyovanni Arzuaga, 24, were both gunned down.
Authorities previously said Perez was unintentionally shot to death by her boyfriend during the frenzy that night.
Lorenzi allegedly shot Arzuaga several times, including once in the head.
READ ALSO | Man arrested in CA for Chicago shooting that killed 2 amid Puerto Rican Day festivities, CPD says
Arzuaga died of his injuries that night. Perez died of her injures a few days later on June 22.
Authorities said Lorenzi is a career criminal who has been arrested nearly 30 times and convicted of seven violent crimes. Before the fatal shooting, he was most recently in trouble for a botched carjacking, according to police.
A judge revoked Lorenzi's bail. The case goes back to court on December 16 for post-trial motions.