“I’m in the trenches right now,” John Branca says. His foxhole is a salmon-pink villa in Beverly Hills. Sunlight spills into the room on to Venetian antiques and Michael Jackson relics: an oversized portrait, whose gaze seems to follow; two original Andy Warhol sketches in turquoise and violet; a leather jacket studded with forks and spoons the star once wore to dinner with Elizabeth Taylor. It’s immaculate to the point of unease.

Branca, 74, is one of the most powerful lawyers in music history, having brokered deals for the Rolling Stones, the Bee Gees, Aerosmith, Bob Dylan, Dr Dre, the Eagles and Motown Records founder Berry Gordy. Today, his firm represents Beyoncé. But he’s still best known for being Michael Jackson’s guy — the man who has spent the better part of 50 years defending the reputation of a deeply complicated cultural icon.

Since Jackson’s death in 2009, Branca has been coexecutor of Jackson’s estate alongside John McClain, a longtime friend of the family. When they took over it was a troubled asset under the shadow of allegations of child sex abuse and the star’s increasingly erratic lifestyle. Jackson died more than half a billion dollars in debt. But Branca helped turn the estate around, making a documentary and a hit Broadway show, among other lucrative deals that have generated over $3bn in earnings — more than any music estate, including Elvis Presley’s and The Beatles’.