Max's appearance and attributes continue from the canon of Ben 10: Ultimate Alien. He is between 65 and 66 years of age and maintains his status and affiliation with the Plumbers. Max first appears in "Pilot - Part 2" at Ben's House, to calm a deeply worried Carl and Sandra that the Plumbers have almost triangulated Ben's location following his kidnapping and subsequent public report by Will Harangue. Verdona appears in one of Max's temporary Plumber stations and brings Max and Cooper along to find Ben.
They find the Rust Bucket 3 and use it to travel to the final destination Verdona was able to track Ben to: Fort Briggs. Verdona leaves for business elsewhere and Max and Cooper arrive in the middle of a hostage situation. Vulkanus is about to kill Gwen, Kevin and Harangue, but Max stops him and negotiates a deal to leave Ben with him and take the others. The Ultimatrix was drained of power earlier, but Max notices that it's charged. Ben calls Max's bluff with Vulkanus and transforms into Cannonbolt and later Ultimate Cannonbolt to destroy Fort Briggs and chase Vulkanus to Bellwood. Harangue escapes the Rust Bucket, but Ben defeats both him and Vulkanus.
Max reappears in "Brothers" after Kevin uses his Plumber badge to call on the Plumbers while under attack from Krill and Wyatt Herman. Flashbacks at the start of the episode show Max training the brothers in the Plumber Academy a year before the events of the original series and how he plans to make them Elites much faster. In the present day, Max, having identified the brothers by their fighting style from surveillance, informs Ben about his history with the brothers and their "disappearance" two years ago. Ben, having captured the brothers, learns that they were blackmailed in 2012 by an anonymous man threatening to kill their family unless they become assassins. The man texts the brothers with a picture of their captive parents, prompting them to commit suicide on the spot.
Max arrives to pick up the brothers but is devastated to find them dead. Ben tells Max everything he knows, and Max takes their bodies to a Plumber station in space. The brothers' parents, who know Max, are delivered safely with a note from the blackmailer, taunting Max and saying the they will meet again. Max crumples the note, but remains immensely determined in finding the man.
Max's personality in Heroes of Evolution contrasts by-the-book ways, fatherly concern, and "old people humor", leaving his characterization relatively unchanged from Alien Force and Ultimate Alien.
When it comes to people he cares for, Max takes great lengths in ensuring their safety and does his best to provide a father figure to those who look up to him. He harbors an unrelentless determination and much like the undertones in the first three series, seems to ignore his age and make fun of himself and his "elderly" stereotypes to show that he won't stop taking risks and enjoying himself.
Like the protagonists, Max was deeply scarred by the death of Krill and Wyatt, and while he is gentle at heart, a more vengeful side to him slowly begins to unfurl in his quest to bring down the man responsible for their downfall. His determination is prominent and his perseverance never falters.
Nonetheless, his lightly belittling sense of humor and tendency to ease up most situations remains prominent during his signs of making fun of suburban lifestyle - while not openly expressing his individuality, Max's characterization allows for him to automatically work against any stereotypes of the "retired old man" - his outlandish and oftentimes strange behavior still takes presence and he's implied to continue the pattern of having extremely strange seafood - this subtle acknowledgement of his stranger qualities seems to be something Ben has inherited.