Shogo Kubo, a skateboarding pioneer who was depicted in the award-winning documentary "Dogtown and Z-Boys," which was later made into a Hollywood feature film, died Tuesday while surfing off Portlock. He was 54.

Kubo, of Hawaii Kai, was found unresponsive about 8:30 a.m. off a beach in the Portlock area, police said.

Paramedics treated Kubo at the scene, where he died at 9:25 a.m. The Honolulu Medical Examiner’s Office said Wednesday that the cause of his death was still pending.

Kubo was a member of a team founded in 1975 from Dogtown, or Venice, Calif., that became known as the Z-Boys.

The team’s outlaw exploits became the focus of the 2001 documentary, narrated by Sean Penn. The documentary served as the inspiration for the 2005 movie "Lords of Dogtown," staring Heath Ledger.

Kent Senatore, owner of Tore Surfboards Hawaii, skateboarded in empty swimming pools with Kubo in Southern California in the 1970s and ’80s.

Senatore, 53, who now lives on the North Shore, said Kubo’s generation paved the way for modern skateboarding’s development.

He said a surfboard shaper named Jeff Ho started a team that became the Z-Boys, and Kubo was an original member.

"They were credited with creating surf-style skateboarding," he said, noting that the tide has shifted as modern surfing now mimics skateboarding. "This guy’s a legend."

He said Kubo became known for the layback move, but could do much more.

"He did some of the highest airs of my generation," he said. "He’s just so underrated."

The movement got its beginning in the late ’70s during a drought in Los Angeles.

"There were endless empty swimming pools," he said. "We were like kids in a candy store, jumping over fences."

He said Kubo also appeared with him in the 1978 BBC documentary "Skateboard Kings" about the skateboarding scene in California.

"He was very humble and quiet," Senatore said. "When he got on that skateboard, he was aggressive. He was beautiful to look at because he had great style."

Peggy Oki, Kubo’s teammate on the Zephyr skateboarding team, which later became known as the Z-Boys, said Kubo was one of the more polite team members.

"He was a very good soul," said Oki, a former professional skateboarder who was inducted into the Skateboarding Hall of Fame in 2012.

She skated with Kubo for about a year when she was in her late teens in the 1970s.

"We used to talk a little bit more because me being Japanese-American as well," she said by phone from her home in California.

Kubo, born in Kagoshima City, Japan, joined the Z-Boys after the group saw him skate.

"I lived just with my father," Kubo said in an interview with the Honolulu Star-Bulletin after the Z-Boys documentary came out. "I think we all needed attention, and Jeff (Ho) and Skip (Engblom) gave us that. We hung out every day together."

In a 2002 interview with the Honolulu Advertiser after the release of the "Z-Boys" documentary, Kubo said, "We were aggressive and confident and stood out because we were so different, like beach bums."

Senatore said he recently met Kubo’s son, Shota Kubo, who also skateboards. He is sponsored by APB Skateshop in Chinatown. Kubo’s family could not be reached for comment.