Alexander Ali Natana earned a Diploma in Store Pest from the Tropical Store Pest Institute in London in 1980 and a degree in Integrated Pest Management from the University of Khartoum in 1991.  Alexander also completed a root and tuber crop training course at Nigeria’s International Institute of Tropical Agriculture (IITA). In 1972, he was assigned as the regional ministry of agriculture as a technical inspector for plant quarantine and pest storage.  He was sent to Renk Scheme in 1997 as the Food Security Coordinator, representing all ten Southern Sudanese states in the regional ministry of agriculture until 2003. 

In 2004, he was appointed director of agricultural engineering, and he built the agricultural engineering unit in Kapuri, Juba.  In 2005, he was appointed assistant director of plant protection. In 2008 he was assigned to establish the Kapuri agricultural center for training tractor drivers. In 2014, he was appointed director of plant quarantine and store pest, a position he maintained until 2024, when he was named interim director of the plant protection directorate. As the DG for Plant Protection, he is dedicated to assisting farmers in overcoming the challenges posed by plant pests and diseases such as locust outbreaks, fall army worms, Quelea quelea birds, particularly in Upper Nile State, army worms, African army worms, fruit flies, milli bugs, legged footed bugs, mosaic diseases, and grain weevils that attack stored produce.  His efforts also include ensuring that farmers across the country are equipped to respond to some insect outbreaks.