Jhon Jairo Velásquez Vásquez was born on April 15, 1962, in Yarumal, Antioquia, Colombia. Details of his early family life are limited, but he grew up in a period of extreme violence and social unrest in Colombia. As a young man, he joined the Colombian National Army and later attended the National Police Academy, although he did not complete his studies there. He later transferred to the Colombian Navy, where he earned the nickname "Popeye" because of his resemblance to the cartoon character. After leaving the military, Velásquez drifted into organized crime, becoming involved with the Medellín Cartel.

He quickly rose through the ranks, aided by his willingness to carry out violent orders and his close ties with cartel leaders. At the height of his career, Velásquez claimed to be a lieutenant commanding half the cartel’s hitmen. His position put him at the center of the brutal criminal operations that defined the Medellín Cartel in the 1980s and early 1990s. He was known for his cold efficiency, strategic mind, and loyalty to Pablo Escobar, the cartel's infamous leader. Despite periods in prison, he maintained his reputation as one of Colombia’s most feared sicarios.

As a top enforcer and assassin for the Medellín Cartel, Velásquez admitted to personally killing 257 people and arranging thousands more murders. His crimes included assassinations of politicians, journalists, police officers, and rival criminals. He was involved in high-profile kidnappings, including those of Andrés Pastrana Arango (later president of Colombia), Francisco Santos (future vice president), and the murder of politician Carlos Mauro Hoyos. He also confessed to being part of the plot to kill presidential candidate Luis Carlos Galán Sarmiento and was implicated in the bombing of Avianca Flight 203 in 1989, which killed 110 people.

Velásquez surrendered to Colombian authorities in 1992 and received a 30-year sentence, the maximum under Colombian law at the time. While imprisoned, he was involved in violent clashes within La Modelo prison and received additional sentences. After serving over 23 years, he was released on parole in 2014. Velásquez’s post-prison life was controversial; he became a YouTube personality, gave interviews about cartel life, and published books and a Netflix-based TV series about his criminal career.

His freedom was short-lived. In 2018, he was arrested and later convicted for extortion, accused of blackmailing former cartel associates. In late 2019, his health deteriorated due to esophageal cancer. He was transferred to La Picota prison in Bogotá for medical reasons and died there on February 6, 2020, at the age of 57. His life and crimes remain a dark chapter in Colombia's history, and his story has been widely documented in films, books, and media.