Levi Aron was born around 1976 and raised in Brooklyn, New York, within an Orthodox Jewish family. His father, Jack Aron, worked at B&H Photo, a business owned by members of the Hasidic community. Levi's mother, Basya, passed away several years before the events of 2011. He lived in the attic apartment of his family's three-story home in the Kensington neighborhood of Brooklyn.

Aron held various jobs, including working as a clerk at a hardware supply company in Brooklyn. Colleagues described him as quiet and socially awkward. At the age of nine, Aron suffered a head injury after being hit by a car while riding his bicycle, which reportedly led to ongoing psychological issues. He had no significant criminal record but had been served with an order of protection in 2007 and received minor traffic violations.​

In his personal life, Aron experienced two short-lived marriages. His first marriage, in 2004, was to an Israeli woman and ended in divorce within a year. In 2007, he married Deborah M. Parnell, a divorced mother of two from Tennessee, whom he met online. This marriage also ended in divorce, and Parnell later reported instances of controlling and threatening behavior during their relationship.​

Psychiatric evaluations conducted after his arrest diagnosed Aron with schizoid personality disorder. He was described as having a "practically blank" personality and was noted to be reserved, apathetic, and sad. Aron also reported experiencing hallucinations and hearing voices. Despite these findings, he was deemed competent to stand trial.

On July 11, 2011, eight-year-old Leiby Kletzky, a Hasidic Jewish boy from Borough Park, Brooklyn, was walking home alone from his day camp for the first time. After missing a turn, he became lost and encountered Levi Aron near a dentist's office. Surveillance footage later showed Leiby speaking with Aron and then entering his vehicle.

Aron took Leiby to a wedding in Monsey, New York, approximately 40 miles from Brooklyn, before returning to his apartment later that night. The following day, Aron went to work, leaving Leiby alone in the apartment. Upon returning and seeing the extensive search efforts for the missing boy, Aron panicked. He administered a combination of drugs to Leiby, including cyclobenzaprine, quetiapine, hydrocodone, acetaminophen, and duloxetine, and then smothered him with a towel. ​

Aron dismembered the body, placing some parts in his freezer and others in a suitcase, which he disposed of in a dumpster in another Brooklyn neighborhood. The disappearance prompted a massive search involving thousands of volunteers and law enforcement. Investigators used surveillance footage and dental office records to trace Leiby’s last known whereabouts to Aron. Police arrested Aron on July 13, 2011, after discovering evidence in his apartment.

Initially pleading not guilty, Aron later accepted a plea deal to avoid a trial. On August 9, 2012, he pleaded guilty to second-degree murder and kidnapping. He was sentenced to 40 years to life in prison and is eligible for parole in 2049.