Exclusive: Rapper speaks in public for the first time about the day he shot his drug-addicted brother • Read the full interview in Saturday's Weekend magazine

Jay-Z, the world's most successful rap star, has spoken publicly for the first time about one of the darkest episodes of his tough upbringing: when, aged 12, he shot his brother.

The rapper, real name Shawn Carter, has a business empire spanning fashion to Broadway and a fortune estimated at $450m, but he grew up in a Brooklyn housing project ravaged by violence.

In tomorrow's Weekend magazine, he describes shooting his brother, who had stolen his ring, and tells how he felt after pulling the trigger: "I thought my life was over. I thought I'd go to jail for ever."

In fact his brother, addicted to crack at the time of the shooting, did not press charges and apologised to his little brother for his addiction when the future star visited him in hospital. "It was terrible. I was a boy, a child. I was terrified," he said.

The shooting is explored in the lyrics of You Must Love Me. "Saw the devil in your eyes, high off more than weed, confused, I just closed my young eyes and squeezed."

In the interview he also describes his surroundings. "Guns were everywhere. You didn't have to go far to get one. Just everywhere," he said. In a housing project in the Bedford-Stuyvesant area of Brooklyn, shootouts were commonplace: "[Guns] were around every day. There were shootouts, but I never shot anyone else. Most people in shootouts don't get shot."

Despite being shot at three times, he was unscathed. "It's like there was some rogue angel watching over us," he said.

With 10 Grammy awards, 11 No1 albums and a supremely talented wife – the singer Beyoncé is herself worth more than $100m – Jay-Z is one of the best-known musicians in the world. Two years ago he defied naysayers at Glastonbury with a critically acclaimed headline appearance on the Pyramid stage, and has proved to have a wide crossover appeal that has helped him amass a huge personal fortune.

His business acumen is widely recognised. While an unsigned aspiring rapper, Jay-Z founded Roc-A-Fella Records, a trail-blazing move with many canny artists, such as UK rapper Dizzee Rascal, following in his footsteps.

CEO of the Roc Nation music publishing and entertainment empire, he also co-owns the 40/40 nightclub chain, a sports bar and lounge in New York and is part-owner of the NBA's New Jersey Nets. When the 40-year-old sold his Rocawear clothing brand to the Iconix Brand Group in 2007 he netted $204m.

This year saw a new revenue stream emerge in the form of the Broadway show Fela!, in which he has an investment, and his Blueprint 3 tour,has grossed more than $1m a concert this year.