Agent Mark Guy confirmed the terms of the deal in an email to The Associated Press.
Cizikas will count $3.35 million against the salary cap through the 2020-21 NHL season. He was at $1 million on his previous contract.
The 25-year-old set a career high in points last season with 30 on eight goals and 22 assists for the Islanders, who made the playoffs.
Cizikas has 29 goals and 54 assists for 83 career points since making his NHL debut in 2012. The Toronto native was a fourth-round pick in 2009.