Comeau, who was acquired from the Calgary Flames at the 2013 NHL Trade Deadline, would have become an unrestricted free agent on Friday.
The 27-year-old had two goals and five points in nine games after joining Columbus. He totaled six goals and 12 points in 42 games combined between the Flames and Blue Jackets.
"Blake is a dependable two-way forward who combines physical play with ability in the offensive zone," Columbus general manager Jarmo Kekalainen said. "We liked what we saw from him at the end of last season as he fit in very well with our team and we're pleased to have signed him to this extension."
The 6-1, 205-pound forward has 67 goals and 148 points in 361 NHL games with the Blue Jackets, Flames and New York Islanders. He set career highs for goals, assists and points in a season with 24-22-46 and 43 penalty minutes in 77 games with the Islanders in 2010-11.