Zennon walked out of school at 16 years old and talked himself into a job in a restaurant kitchen at Titirangi’s Barossa. After six months, he moved to Auckland's Euro restaurant, then helmed by Simon Gault. Three years later Zennon moved to Australia, where he honed his skills in some of Australia’s most esteemed kitchens. Zennon returned to Cibo in Auckland before going on a nine-month culinary tour of the world, during which he ate at 34 of the World’s Top 50 restaurants. He joined Auckland restaurant Paris Butter in 2019 as sous chef and bought the business in early 2023, becoming head chef and co-owner.

In August, Zennon was named Chef of the Year in the 2023/2024 Cuisine Good Food Awards.