He could have become a restricted free agent July 1.
"I'm thrilled to be with the Coyotes for the next six years," Chychrun told the Coyotes website. "Arizona is where I want to be. I'm excited about our group moving forward and I can't wait to be a big part of it."
The 20-year-old defenseman made his season debut against the Detroit Red Wings on Tuesday after missing Arizona's first 16 games because of knee surgery he had in April.
Chychrun had 14 points (four goals, 10 assists) and averaged 20:15 of ice time in 50 games last season. Selected by Arizona in the first round (No. 16) of the 2016 NHL Draft, Chychrun has 34 points (11 goals, 23 assists) in 118 games.
"We are extremely pleased to sign Jakob to a six-year contract extension," Coyotes general manager John Chayka said. "Jakob is a young, highly skilled defenseman with an incredibly bright future. He has battled through some adversity with injuries the last two years, but we remain confident that he has the necessary size, talent and work ethic to be one of our core players for many years to come."
