NCIS's Brian Dietzen on Emotional Ducky Tribute Episode and What He'll Miss About David McCallum

David McCallum is getting a hero's send-off on NCIS. The late actor, who played chief medical examiner-turned-NCIS historian Dr. Donald "Ducky" Mallard on the long-running CBS procedural for two decades, died Sept. 25, 2023 at the age of 90. News of his death shattered the NCIS family. But it also presented an opportunity to pay tribute to a screen legend and honor a beloved TV character. 

Doing justice to Ducky's farewell episode — titled "The Stories We Leave Behind," airing Feb. 19 — was a "daunting" and emotional task, NCIS star Brian Dietzen admitted to TV Guide. How does one adequately sum up a lifetime's worth of moments into 40 minutes? "That's 20 years of getting to spend with the TV and film legend that I'm blessed to have experienced," said Dietzen, who co-write the episode with his writing partner, Scott Williams.

Even though Ducky's death is the primary focus of the episode, the NCIS team is presented with one of the last cases he was secretly working on up until he died, utilizing a wealth of information and treasures he left behind that could prove useful in the future. As a result, the crew is left reminiscing about the past, leading to key flashbacks and scenes with team members who have since departed, including Mark Harmon's Jethro Gibbs.

Ahead of the episode, Dietzen hopped on Zoom with TV Guide to discuss how he approached co-writing Ducky's tribute hour, how he picked key scenes from the past to include, and how McCallum's presence will be felt moving forward. He also teased upcoming romantic challenges facing his character, Jimmy Palmer, in his relationship with Jessica Knight (Katrina Law).

How are you feeling about heading into Season 21 of NCIS?
Brian Dietzen: It feels wonderful, if I'm being honest. I would think that someone being on a show for an extended period of time like this, you might start to feel a little bored. But the show has found a way to recreate itself year after year, and while some of the faces have changed over the course of the years, the idea [is] that we always want to come up with new and better concepts, relationships, and crimes. We never stop trying to do better each week. It feels fresh, it really has. A couple of years ago with the addition of Gary Cole and Katrina Law, that really helped open up a whole world of possibilities for us.

This coming episode is a special one as it pays tribute to the late David McCallum, who played Ducky. How did you come to co-write this episode, and was there a certain pressure to do it justice?
Dietzen: It was certainly daunting in a way. The way it came to be was we had a work stoppage last year due to the writers strike and the actors strike. And then when we got the awful news that David passed away [on Sept. 25, 2023]. My co-writer, Scott Williams, stepped up and said, "I'd love to write Ducky's farewell episode. If it's okay with everyone, I'd like to have Brian co-write it with me." Our showrunners, Steve Binder and David North, were more than supportive and said, "Yes, absolutely. That's a perfect fit." If you're asking me to help, I would be honored to, and this is an important character for TV history. More importantly, he's a good friend. To be able to honor him with the script was of paramount importance for me. There's definitely a little bit of pressure added in there because of that.

Did you have any guidance from the showrunners before you and Scott sat down to write the episode? How did you approach writing this hour?
Dietzen: We wanted to tell an NCIS story, so we wanted it to be an NCIS show, meaning it has a case that we're solving. But we also wanted that case to thematically link up with the loss of one of our loved ones. We wanted to have the character of Ducky be instrumental in solving the case, but we didn't want it to be so straight down the middle that the case was about him in any way. We had it thematically linked to loss and to the stories that we leave behind for someone else.

While this is certainly not a clip show of any sort, there are more moments and scenes where you're going to see Ducky over the past 20 years. What was important to both Scott and I was that we get to see Ducky communicating with the team — and not just our current team but our past family members that this franchise is built upon, including Gibbs, Tony, Ziva, Abby, and all the rest. There's a long-standing family that we've had for 20 years, and to be able to honor their relationship with him with some scenes here and there was of big importance.

What did it mean to you to have a big hand in shaping this farewell episode? And personally, having worked with David all these years, what will you miss? 
Dietzen: This episode was all about reminiscing while we were shooting it. There were a lot of stories being shared. I definitely had some tears while writing it and also while filming it. He was a good friend and he was a great man. Over the course of 20 years, you get to know someone pretty darn well, and you end up spending more time with them than you do sometimes with your own family members. The sadness, of course, was there, and the reflection and stories were also there. And we wanted to make sure that when we told this story, it wasn't just about the sadness of what happens when we lose someone, but also the celebration of what we have in our lives because we had them. That's 20 years of getting to spend with the TV and film legend that I'm blessed to have experienced. Within the storybook world of NCIS, our team was lucky to have this character of Ducky. To be able to see this team come together and coalesce and remember together and laugh together and celebrate together and, of course, cry together, it was nice to be able to show that full spectrum.

Did you have any conversations about bringing other people back from the past for this episode? 
Dietzen: What I was really happy with is that we got to show Ducky with his team from the past. We got to see him with a lot of different team members and show his adventures and his kind ear that was always there for all of his teammates over the years. We got to honor the relationships that he's had with characters from past iterations of our show and also from the present. I think people will be happy with what they see.

How did you determine the specific scenes you wanted to include to highlight Ducky's various relationships with the team? You have 20 seasons of footage, so what was the process in identifying the best lines or moments? 
Dietzen: It was a team effort, for sure. I was joking with a few people saying a lot of it came down to having a Paramount+ subscription and literally scrubbing through [episodes] until you see David's face and then watch the scene. A lot of the scenes, I knew which ones I wanted to use, and Scott knew as well. When we first got together at the writers' table back in October, I said, "I know the speech I want Ducky to end with, that we're going to leave with. I know exactly which episode that's going to be." Our showrunners had thoughts as well on different scenes — never telling Scott and I, "Here's a mandate," of any sort. But there were ideas flowing from different people, which was really helpful because I'm not the only one who experienced scenes with him. These are people who spent dozens of years with him who loved writing for him. So I wanted to honor as much of that as possible. 

How much of Ducky's presence will be felt after this episode?
Dietzen: He'll be ever present. There are going to be remnants of the force of Ducky in that room forever — emotionally, spiritually, but also in physical form. He's left us with a few tokens of him and the work that he's done that we're going to be able to reference from now until the end of the show. But even the episode that we're filming right now, I have two different lines that reference Dr. Mallard. I don't see saying goodbye to this character as washing the slate clean of his presence. I'd say it's an episode to honor him and it's a show to celebrate what he's done. It certainly is a goodbye, but it doesn't mean that we'll lose sight of the man that started that autopsy room downstairs.

Aside from grieving Ducky's death, what can you share about what Jimmy will be going through this year?
Dietzen: Jimmy's had a rough few years. Between losing his wife, almost dying, having his team change up. But we've also seen him fall in love, to the point where he's blurting out "I love you" in the bullpen and being very embarrassed about it. There's been a lot of downs for him, but there's also been some ups. We're going to see some challenges to some of those ups, meaning his relationship with Jessica Knight. It's going to be front and center in a couple of episodes coming up this season. Because now we've established they love one another, what happens next? Very rarely does someone say "I love you" and someone else says "I love you," and then for the rest of their lives, everything's perfect. There are going to be some bumps along the road. There's a future episode where Jimmy meets Knight's father, and things maybe don't go exactly to plan. 

Is there still something you'd like Jimmy to experience or do?
Dietzen: They've given the character so much to do over the course of these years, and honestly, it's been such a pleasure to play the transformation of this character from, "Gosh, I don't feel confident in what it is I do. I'm intimidated," into the character he is now. Everyone gets intimidated, and sometimes he's still a little uncertain, but for the most part, he's grown a lot. I loved playing that transition and retaining that optimism that Jimmy Palmer has been known for. That's one thing I hope to retain, no matter what this character goes through, is his ability to look on the bright side.

How have you felt about the evolution of Jimmy Palmer as a character and charting that progress along with the viewers from Day 1 to where he is now?
Dietzen: It's been a huge journey over the course of 20 seasons, and this guy is quite different from the nervous intern that we met for a day in Season 1. The thing that I'd like to continue to see is audiences are looking for familiarity, and they're looking for stories that have lots and lots of episodes. Right now, we live in a world where people are also looking for the positive. We can tune into any news channel any hour of the day and we can see how awful things are. There are a ton of things happening in the world right now; injustices being perpetrated left, right, and center, and it can bog you down, which is why certain shows that have taken off have an optimistic take or an optimistic character. Ted Lasso did it so well of having a character who's saying, "I know things are bad right now, but I'm going to choose to look on the bright side," and Jimmy Palmer has always had that perspective. If that is refreshing for people in any way, rejuvenating or restorative, I am happy to be the guy that gets to portray that every week. I hope to be able to retain that energy with this character for a long time.

NCIS airs Mondays at 9/8c on CBS.