Hudson & Rex is a Canadian adaptation of the Austrian–Italian series Kommissar Rex (Inspector Rex), which had aired in Europe for nearly thirty years before the Canadian production acquired the rights.

The success of Hudson & Rex in English-speaking countries led to a new production of Kommissar Rex in Europe, expected to return to television there in 2026.

The dog Diesel vom Burgimwald, who originated the role of Rex in the Canadian series, is a 15th generation descendant of Santo, the original dog who starred as Rex in the 1990s Austrian-Italian series.

Diesel vom Burgimwald was a Canadian Kennel Club grand champion and a direct descendant of the Trienzbachtal bloodline, related to VA5 Elch vom Trienzbachtal, the great-grandfather of Santo, the original European Rex.

Diesel had never appeared on a show before Hudson & Rex; he received mobility training before being cast and continued training on non-shooting days to prepare for future scripts, according to his owner-handler Sherri Davis.

On set, Diesel and his fellow canine actors received full star treatment, including their own trailers, a chef, and a chauffeur.

Diesel and his character Rex were made honorary firefighters with the St. John's Regional Fire Department during filming of an episode called "Fast Eddie's," which became part of the episode "Flare of the Dog".

Diesel vom Burgimwald died of cancer in August 2024 during filming of season 7, though news of his death was not released until February 2025; his nephews Dillon and Dante and distant cousin Dreamer, who had already been acting as his stand-ins, took over the role starting in season 7, episode 3.

German Shepherds Izzy and Iko, both nephews of Diesel, served as stunt doubles for Rex's action scenes throughout the original run and continue in that role in later seasons.

Three of Diesel's real-life puppies played the dogs Buster, Duff, and Kona in the season six episode "Claws Out".

In January 2026, the Toronto Star reported that Diesel and three other dogs had been poisoned in October 2022.

Lead actor John Reardon was absent for most of season 7 while recovering from tonsil cancer, and was replaced by a new character, Detective Mark Hudson (played by Luke Roberts), for season 8; Reardon was set to return in season 9.

Filming takes place at various locations across St. John's, most prominently on the Memorial University of Newfoundland campus, where the Bruneau Centre (formerly the Inco Centre) doubles as the fictional St. John's Police Department headquarters.

Season one was originally meant to have 16 episodes, but only 13 aired as part of season one, with the remaining three episodes broadcast as the start of season two.