"The films that I did prior to 'Pirates,' ... not everything but a lot of it, was sort of by industry standards, not blockbuster stuff. So I wasn't ever blockbuster material," said Depp in a recent interview.
But that's not to say he didn't have fun during those years.
"I've been lucky enough to be involved in some very small and different independent films throughout my career and I've been able to be involved in, you know, a couple of films that shocked everybody, especially me," he said.
Since 2003, Depp has played the flamboyant captain in four hugely successful "Pirates of the Caribbean" films, with a fifth installment slated for 2015.
At age 50, he is still one the hottest names in Hollywood and about ready to launch another big-budget summer flick, "The Lone Ranger."
"The only thing I can equate it with is luck. There's no other reason," he said of his career longevity. "The fact that I was able to survive through that 15 years of just bouncing around doing (indie) movies and now still to end up here is amazing."
The Golden Globe-winning actor plays the famed Native American character Tonto in the upcoming Disney reboot of "The Lone Ranger," which is opening Wednesday. He said his children, Lily-Rose, 14, and Jack, 11, can't wait to see it.
"They're pretty excited about this one," Depp said while promoting the film in Santa Fe, N.M., where part of the movie was filmed. "You know, of course, they thought it was insane when they watched me play Tonto, but now they're looking forward to this one."
Despite his success, Depp recognizes that life on Hollywood's A-list can be fleeting.
"I certainly wouldn't expect that it is one of those things that is going to stick around forever and ever," he said. "The clock ticks, the time's up and the next guy steps in or whatever and that's how it goes."
When he's not busy making films, Depp said music continues to be his main inspiration. Writing, playing guitar and one-off performances with artists like Keith Richards, Aerosmith, Black Keys, Alice Cooper and Marilyn Manson keep his creative juices flowing.
Depp says that in the last couple of years, he's had "sort of a rebirth of my relationship with music. So I've been playing more and writing more and it's led to invitations to play with people."
Depp, who celebrated his milestone birthday June 9, refuses to take a single day for granted.
"Just to be here still is pretty amazing," he said. "Every day should be some sort of celebration. So yeah, I guess when you hit 50 finally ... it's just happy to still be around."