Llewellyn was born in Pietermaritzburg in 1976 and grew up in the small town of Kokstad, KZN. His family later moved to Pretoria 1987 where he attended Lynwoodridge Primary School.
From an early age, Llewellyn had a keen interest in nature and all out-door activities. He was an active member of the Catamaran Club; Pretoria Canoeing Club; St. Albams Hockey Club and the Wildlife Society of South Africa.
After matriculating from Willowridge High School in 1993, Llewellyn registered for a certificate course in Environmental Biology with UNISA in 1994. Between 1995 and 1996 he attended the diploma course in Nature Conservation at the Pretoria Technikon (now know as the Tshwane University of Technology).
In 1997, as part of the diploma's experiential training, he was employed as an Interpretive Services student at Letaba Rest camp, Kruger National Park (KNP). After approximately 100 tourist drives in under six months, Llewellyn transferred to the Alien Plant Section of the Nature Conservation Division.
Here, under the leadership of Wayne Lotter, he began a career in conservation management and developed his passion for research.
He was appointed Alien Biota Manager in 1998, where he was responsible for over 300 staff members and more than R3 million within the KNP Working for Water Program. He successfully completed his B-Tech: Nature Conservation through Pretoria Technikon in 1999. In 2000 Llewellyn was transferred to the Scientific Services division as Programme Manager: Invasive Species Research.
During that same year he received a bravery award, cited as follows: "Llewellyn Foxcroft risked his life when four tourists were trapped on the roof of their vehicle in the Sabie River, during the floods of February 2000. Tying a rope to a tree, he assisted all four tourists to safety. One of the tourists could not swim and under extremely dangerous circumstances Llewellyn brought her to safety. The Sanparks honours him for his honourable and brave deed".
Llewellyn completed his M-Tech: Nature Conservation in 2003, again through the same institution, Pretoria Technikon. His thesis, tiled "Factors influencing the distribution and abundance of an invasive plant, Opuntias stricta, and its biological control agent, Cactoblastis cactorum in the Kruger National Park" was awarded the best Masters thesis in the faculty of Agricultural Sciences. That same year he was honoured with KNP's outstanding service in the workplace award.
In 2004 he registered for a PhD with Prof Dave Richardson though the University of Cape Town's botany department. During the period 2004-2007, he was fortunate to travel to and work with top international scientists from USA, Australia, Tanzania, Botswana, Reunion Island, Czech Republic and UK.
From January 2007, Llewellyn was appointed as the editor-in-chief for the Sanparks scientific journal, "Koedoe", in tandem with his position as Scientist: Invasion Ecology.
His PhD thesis, 'Pattern and process of plant invasion in an African savanna ecosystem, with emphasis on multiple spatial and temporal scales' has resulted in five peer-reviewed scientific publications to date. Another two are in preparation and ultimately his PhD was accepted with no corrections.
He will be attending his graduation ceremony in early December 2007. Invasive Alien Species are regarded as the second greatest threat to biodiversity, globally. However, as one colleague commented, 'With Llewellyn's expertise the fate of our national parks is in good hands.'