Reece Fakhr was arrested on Tuesday by strike force detectives and Australian Federal Police. Police allege Fakhr is a key player in the high-profile Coconut Cartel organised criminal network and that they found incriminating evidence on a mobile phone he left at the scene of the shooting.
Fakhr has been charged with 10 offences, including conspiracy to murder, kidnapping, arson and directing a criminal group. He is not related to the child.
The boy, who cannot be legally identified, was fatally shot in the face inside an apartment in the Moda complex in Norwest. Investigators believe he may have been one of several people handling an illegal firearm when it discharged. The boy's mother and several 18-year-old men were inside the apartment at the time but were not injured. Several of the men fled before emergency services arrived. The child died in hospital two days later.
The boy's father, a convicted cocaine dealer, has paid tribute to his son on social media.
Police allege Fakhr was attempting to leave the country when he was intercepted at Sydney International Airport. The arrest follows a strike force investigation into the shooting.