The extension begins next year and will keep Braun under contract with the Sharks through the 2019-20 season. According to Braun's agent Neil Sheehy, the deal is worth $19 million.
"Justin has emerged as one of our most well-rounded and dependable defensemen," Sharks general manager Doug Wilson said in a statement. "We feel Justin has just scratched the surface of his talent and we are excited to have him under contract for the next six seasons."
The 27-year-old has spent four seasons with San Jose and registered 17 points last season. He was second on the team in average time on ice per game and tied a franchise record with eight blocked shots on Nov. 29.
The Sharks begin the 2014-15 season on Oct. 8.
- Molly Geary