Drake, Josh and Nancy were all on The Amanda Show (1999), before the program begin. This is a spin off the latter similar to how Kenan and Kel both appeared on All That and eventually had their own spin off of that which was Kenan and Kel and was also written by Dan Schneider.
Much of the supporting character's would later make guest appearances on other shows created by series creator Dan Schneider. Examples include Craig and Eric making a small appearance in the iCarly episode "iStart a Fan War" and Helen made a special guest appearance in the Victorious episode "Helen Back Again".
The scene where Drake and Josh are working at a sushi conveyor belt was inspired by the famous American show, I Love Lucy (1951). It was based on the episode where Lucy and Ethel are working at a chocolate conveyor belt. Also there is a brief clip of it on the Victorious episode "Who Did It To Trina"
In the "Really Big Shrimp" movie, one of the movie titles shown playing at the Premiere Theater where Josh works is "Lil Lisa 22", a reference to Zoey 101 (2005)'s character Michael Barrett's nickname for his girlfriend.
Josh constantly mentions how he admires Oprah Winfrey in a multitude of episodes. In reality, Josh Peck is a fan of her. In Josh Runs Into Oprah (2006), Drake gets him Oprah tickets for his birthday only to accidentally run her over.
Walter's car throughout the series is a royal blue Ford Mustang convertible that seems to change to a newer model every season. In Season 1 it is a 2004 model but by Season 4 it switches to the newer 2007 body style.
When Drake Bell guest started on Grandfathered (2015), three references of the show were made. 1. Drake says Josh's character (Gerald) reminds him of his stepbrother. Upon asking about his stepbrother, Drake's character reveals he's in jail for stalking Oprah. 2. After an argument between Drake and Josh's characters, Josh demands Drake leave to which Drake responds, "Don't tell me what to do." 3. After coming to an agreement, Josh's character enthusiastically shouts, "Hug me, brutha!" to Drake and proceeds to hug him.
Miranda Cosgrove, Jerry Trainor, and Nathan Kress are part of the main cast of iCarly. Jerry has appeared in several episodes of Drake and Josh when Nathan has appeared in only one. Meanwhile, Miranda was in every episode.