Depay is starring for the Netherlands at Euro 2020, while he looks likely to join Barcelona on a free transfer later this summer.
The 27-year-old is one of the most feared forwards in Europe, combining speed, strength and excellent technique.
"I think he's a maverick," Ferdinand said on BBC Sport during their Euro 2020 coverage about Depay, who was at United from 2015 to 2017.
"He's a new-age type of personality who embraces everything of the lifestyle of a football player and beyond, and some people who are old school don't like that and it's taken time for someone even like me to adapt to that."
Asked why the Dutchman flopped in Manchester, Ferdinand added: "I think it comes down to numerous things. Timing, the right time and right place, and maturity, he may have gone there too young.
"And coaching, the right coaching at the right time."