Commission spokeswoman Sarah Christie said Douglas died Sunday evening at his sister's house in La Quinta outside of Palm Springs.
"He loved the desert as much as he loved the coast," she said.
Friends and colleagues remembered Douglas as a champion for preserving California's coastline.
"His vision and leadership over nearly half a century has shaped a coast that is accessible to all and whose beauty has been protected," California Natural Resources Secretary John Laird said in a statement. "Peter is an inspiration to me for the thoughtful work he has done protecting our coast, and the unrelenting commitment he showed to his work even in the final year of his life."
Assemblyman Jared Huffman D-San Rafael, praised Douglas as a "great friend and a hero to all of us who care about the environment "
"He was a unique combination of warrior and philosopher and he was green to the core," Huffman, who chairs the Assembly Committee on Water, Parks and Wildlife, said in a voicemail message.
Douglas, who was appointed to the commission director post in 1985, stepped down late last year. He had previously been on sick leave related to his lung cancer.
"It was a very difficult decision and it was disease driven," he told the Associated Press at the time of his retirement announcement. "I'm at peace with it - it's been an incredible 41 years. It's been a meaningful, purposeful legacy."
Douglas previously worked as the agency's Chief Deputy and as a legislative aide and committee consultant, where he helped draft and win passage of the ballot measure that created the commission.
Douglas is survived by his sister, Christina Douglas, a brother, Dieter Claren, two sons, Vanja and Sascha Douglas, his former wife Rotraut and two grandchildren, Charlie and Madelina. He asked that in lieu of flowers donations are made to a fund to support coastal work fellowships and a coastal conservation project created in his name.
PHOTO CREDIT: PHOTO CREDIT: A Wednesday March 30,2005 file photo showing Peter Douglas, executive director of the California Coastal Commission, at in his office in San Francisco. Jeff Chu, Associated Press.
Editor's note: This post was updated at 10:37 a.m. with statements from Laird and Huffman.