Harmon made an appearance on the episode as the Leroy Gibbs via webcam, checking in on the New Orleans team as leader Dwayne "King" Cassius Pride (Scott Bakula) fought for his life following getting shot.
During the quick scene, Gibbs is seen calling in to the team's office and talking to LaSalle about how their leader is doing.
"How's he doing?" he asks.
"Honestly, not good," LaSalle says, holding back his emotions.
"You stay strong," Gibbs says before LaSalle asks about Leon Vance's condition after being rescued, Gibbs reveals he's on the mend.
"Your suspect Amelia Parsons... we sent you a classified file on the shooter," he reveals she is CIA and works with Stone, a former nemesis of Pride's who died a year ago. Meaning the shooting was a personal hit on Pride.
Before signing off, Gibbs reassures LaSalle.
"We know how much Dwayne means to you. You take it personal... You use those feelings and make it personal, you do what it takes to get Amelia," he says.
Christopher LaSalle is receiving some sage advice from Gibbs. He should feel his feelings, and put them to work. #NCISNOLA— Becky, USMC (@DuchessofBruce) September 26, 2018
This is not the first time Gibbs has made an appearance on NCIS: New Orleans. He made a quick appearance on the 2017 episode "Pandora's Box: Part II," the appearance in the season five premiere marks his fourth appearance in the spinoff series.
As previously reported, Harmon has not appeared on NCIS: Los Angeles, despite being featured in the backdoor pilot for the LL Cool J-led spinoff on NCIS.
Season five of NCIS: New Orleans is coming with some changes to the fan-favorite crime procedural.
The show is set to introduce a new character that will help the team as Pride recovers from his fateful injury. Necar Zadegan (Girlfriends' Guide to Divorce) is joining the cast as Special Agent Hannah Khoury.
Former Cosby Show star Geoffrey Owens is also set to guest star in a pivotal role in episode six of the new season as Commander Adams, who helps Pride with medical and spiritual advice.
The new season also brings with it series' landmark 100th episode, which is set to air on Oct. 23. The episode will reportedly include musical performances by Nathaniel Rateliff & the Night Sweats.1comments
According to TVLine, the episode will also feature the return of Cassius Pride (Stacy Keach), Pride's father, who after finding himself on parole and released from jail, he finds himself connected to a new case the team investigates.
NCIS: New Orleans airs Tuesdays at 10 p.m. ET on CBS.