Brancato, 32, is known for his roles in the film "A Bronx Tale" and on the TV show "The Sopranos." He was arrested in 2005 in connection with the shooting death of off-duty police Officer Daniel Enchautegui.
Prosecutors contend Enchautegui was killed when he caught Brancato and Steven Armento breaking into a house, which allegedly belonged to a man who had previously supplied Brancato with drugs.
Enchautegui is said to have confronted Brancato and Armento, shooting both.
Prosecutors said Armento then shot Enchautegui in the chest and killed him. Armento was convicted of first-degree murder last month and sentenced to life in prison.
Brancato's murder and burglary trial in State Supreme Court in the Bronx began Monday.
The New York Times said the actor's lawyer Joseph Tacopina asked the jury during opening statements not to "compound one tragedy with another by taking the life of an
innocent individual who sits before you in this trial."
Tacopina said Brancato was trying to get the attention of his drug dealer and not attempting to burglarize his house at the time of the slaying. The attorney also claimed Brancato didn't have a gun or know Armento was carrying one.
"The only person responsible for (Enchautegui's) death is not in this courtroom today," the Times quoted Tacopina as saying. "That person is Steven Armento, not Lillo Brancato."