The tributes continue to pour in on social media—and in the real world—for Harris Wittles, the Parks and Recreation co-executive producer who died on Feb. 19 at the age of 30 of an apparent overdose . Wittels, a widely admired, beloved writer and standup who penned key episodes of the NBC small-town comedy, was remembered as “the funniest comedy writer out there” by his close friend and Parks star Aziz Ansari , and castmate Amy Poehler spoke poignantly about him a few days ago at an event, saying: “I lost a dear, young friend in my life who was struggling with addiction.” (The show will honor his memory during the end credits of the series finale, which airs tonight.) Below, Parks cast member Jim O’Heir tells EW how he’ll miss— and remember—his friend and colleague.

“Harris had a tremendous impact on me, as he did on many people. He was a driving force behind a show that made people laugh and cry—both on set and in homes across the country. The first memory of Harris that really comes to mind is when I was reading Sarah Silverman’s book The Bedwetter, and there was a straight-up picture of his penis. I thought, ‘Any guy crazy enough to publish that is someone I want to be friends with.’ You could say Harris was the funny guy on set, the guy to make you break the most—which is saying a lot. He always knew just what to say. There were multiple times when a scene wasn’t clicking and he would shout out a one-liner that would have everyone on the floor. He made you laugh and was generous with his own laughter. He was so damn quick—it’s just so rare to see that kind of talent. It was no secret that Harris had battled addiction. He was very vocal about his struggle and I remember him talking about it during a standup set. We’ve lost a great mind and, more importantly, a great person. I’m heartbroken for his family, friends and fans who know what a gentle soul he was. I’ll really miss him. He was, and will always be, a member of our Parks family.”