"I want thank the Pittsburgh Steelers for seven incredible years! They took a chance on a little known guy from Ozark, Alabama, which was all I needed. For that, I will always be grateful to the Rooney family, Kevin Colbert, Omar Khan, Coaches Tomlin, Mitchell, LeBeau, Butler, and the entire Steelers organization," McLendon said in a statement.
"I will miss my brothers in Pittsburgh, and the amazing fans of Steelers Nation. But I am excited to become part of a great New York Jets organization. I look forward to continued success on the field, and to becoming part of the New York Jets family."
After being outbid for Harrison, a three-year starter, the Jets turned their attention to McLendon. They met with him last Friday.
Without a viable replacement for Harrison on the roster, the Jets felt they had to turn to free agency. McLendon will be surrounded by three talented defensive ends: Muhammad Wilkerson, Sheldon Richardson and Leonard Williams.
The Jets on Wednesday also agreed to a two-year, $7 million contract with defensive end Jarvis Jenkins.
Coach Todd Bowles prefers a 3-4 scheme, but the Jets also play in a 4-3 front at times.
The Jets were approximately $2.5 million under the salary cap, so they will have to make a move to fit McLendon under the cap. Longtime left tackle D'Brickashaw Ferguson, who has a $14.1 million cap charge, could be released or asked to take a significant pay cut.
McClendon completed a three-year contract that paid him $2.25 million in 2015.
McLendon, 30, was limited to mostly rushing downs last season, playing 34 percent of the defensive snaps, but he had hoped to rush the passer more. He finished the season with 14 tackles and one sack.
He is reliable against the run, helping the Steelers rank among the top five in rushing defense for much of last season.