McLendon was signed by the Steelers as an undrafted free agent on April 27, 2009. He was a final cut on September 5 but re-signed to the practice squad the next day. He was released on November 25 but re-signed on December 2. He was signed to a reserve/future contract on January 7, 2010. McLendon was a final cut for the second straight season when he was waived on September 4, 2010. He was re-signed to the practice squad the following day. The Steelers signed McLendon to their active roster on September 18 and he appeared in their game at Tennessee. He recovered a fumble in that game and made one tackle. He was waived again on September 20 but re-signed to the practice squad on September 22. On October 2, quarterback Dennis Dixon was placed on injured reserve and McLendon was called up again. McLendon was waived on October 7 to make room for Ben Roethlisberger, who returned from his 4-game suspension. McLendon was re-signed to the Steelers' practice squad on October 11. McLendon was again signed to the active roster on October 30. He played in seven games for the entire season, recording one more tackle bringing his total tackles for the season to two. The Steelers finished the season with a 12-4 record to clinch the AFC North, and eventually reached Super Bowl XLV, only to lose to the Green Bay Packers 25-31. In the 2011 season, McLendon appeared in a career high fourteen games. He totaled 13 tackles with one sack. For the 2012 season he played in all 16 games, registering seven tackles and two sacks. After the season, McLendon became a restricted free agent. McLendon visited with the Green Bay Packers before resigning with the Steelers for a three-year deal worth $7.25 million, including $1.675 million guaranteed. In the 2013 season, he appeared in 14 games with 33 tackles and a forced fumble. In 2014, he played in 12 games with 22 tackles and a sack. In 2015, he appeared in all 16 games for the first time of his career, finishing the year with 14 tackles, a sack,
On March 16, 2016, the New York Jets signed McLendon to a three-year, $12 million contract with $4 million guaranteed. Making his first start for the Jets on September 11, 2016, McLendon had tied a career high 2 sacks of the team's 6 sacks in the Week 1 loss against Cincinnati Bengals. On March 14, 2019, McClendon re-signed with the Jets. He signed a one-year contract extension on October 12, 2019 through the 2020 season.
