Coming out of Florida Atlantic, Hendrickson was projected by the majority of NFL draft experts and scouts to be a third or fourth round pick. On January 21, 2017, he attended the 2017 East-West Shrine Game and recorded a strip/sack. He was named the Defensive Player of the Game but lost with the East to the West 3-10. He received an invitation to the NFL combine and completed nearly all of the requited combine drills but chose to skip the bench press. His time in the 40-yard dash (4.65), tied for seventh among all defensive linemen. On March 30, 2017, Hendrickson participated at Florida Atlantic's pro day, had 18 reps on the bench press, and performed positional drills. 27 NFL teams had scouts and team representatives attend to scout Hendrickson and ten other prospects. He was ranked as the 13th best defensive end prospect in the draft by NFLDraftScout.com.
The New Orleans Saints selected Hendrickson in the third round (103rd overall) of the 2017 NFL Draft, using a third round pick originally acquired from the New England Patriots in exchange for Brandin Cooks.
On June 2, 2017, the New Orleans Saints signed Hendrickson to a four-year, $3.17 million contract that includes a signing bonus of $706,288.
He competed with Darryl Tapp, Alex Okafor, Obum Gwacham, Al-Quadin Muhammad, and Alex Jenkins throughout training camp for the role as the starting defensive end. Head coach Sean Payton named him the backup defensive end to Cameron Jordan and Alex Okafor to begin the regular season.
He was unable to appear in the Saints' season-opening 19-29 loss to the Minnesota Vikings due to an illness. On September 17, 2017, Hendrickson made his professional regular season debut against the New England Patriots and recorded three combined tackles in the Saints' 20-36 loss. The following week, he earned two combined tackles and sacked Carolina Panthers' quarterback Cam Newton during a 34-13 victory. In a Week 6 matchup against the Detroit Lions, he made two pass deflections as the Saints won 52-38.
In the 2018 season, Hendrickson appeared in five games in the regular season and recorded eight combined tackles and four quarterback hits. In the 2019 regular season opener for the Saints, Hendrickson recorded two sacks against the Houston Texans on Monday Night Football.
Hendrickson was raised by his parents Collie and Louise Hendrickson. His father played football at Missouri Southern State University. During his time at Florida Atlantic he majored in criminal justice.
Hendrickson married his wife, Alisa Chernomashentsev on July 5, 2020.