Hennie has started his career as a forester with the Department Environmental Affairs and forestry. After 10 years he moved to Western Cape department of Nature Conservation as Mountain catchment manager. He then resigned and moved to Cape town where he was a reserve manager for the City of Cape Town on Table Mountain Nature reserve. From he moved over to South African National parks as a section manager on Table Mountain National Park. He resigned in 1999 and joined Ubuntu Environment cc as Conservation Management Consultant. In 2004 he joined Blue Sun Forestry and Environmental management as CEO. In 2006 he joined GSG Attorneys as Environmental Law Practitioner. In 2007 he left and joined the Keurbooms River Game trails as conservation manager. In 2014 he left their services and joined the Greater Stutterheim Fire Protection Association as FPA manager. From here he joined Working on fire as Provincial Operations Manager for Kwa Zulu Natal Province till 2017. He then joined Chuma Wildfire and Conservation Services at partner and Marketing manager.
His qualifications amongst others includes a National Diploma in Forestry; National Higher Diploma in Conservation (Cum Laude) and a Masters Degree in technology Nature Conservation (Cum Laude); Fire Boss 3; Incident Command level 3; ICS Operations Section Chief.