Born David Mortlock on 27 August 1953, he grew up in Barking, Essex, UK, later moving to Basildon New Town, where he attended Barstable School. He studied environmental sciences at Lancaster University, graduating in 1975. After several years as a musician, he commenced a PhD study on soil erosion modeling at Brighton Polytechnic, under the supervision of geomorphologist John Boardman. Subsequently, he worked with Boardman at the University of Oxford's Environmental Change Unit (now the Environmental Change Institute).
Publications include the first quantitative study of the impact of climate change on soil erosion by water, and a novel modelling study of soil erosion in prehistory together with archaeologist Martin Bell. In 1996 he began work on a self-organising systems model for rill initiation and development, RillGrow. He is also responsible for the Soil Erosion website. Favis-Mortlock was elected a Council Member for the British Society of Soil Science, 2001–2003, and a member of the Executive Committee of the British Geomorphological Research Group, 2003-2006. Until 2010 he was a lecturer at Queen's University Belfast, Northern Ireland. He has now returned to the Environmental Change Institute.
Favis-Mortlock is also a musician; in 1978 he formed a Banbury-based folk group named after the nearby Rollright Stones, together with Adderbury morris dancer Bryan Sheppard (now a member of The Hookey Band). At one stage, the Rollrights included fellow fiddler Chris Leslie on bass guitar. The group supported Fairport Convention and recorded with Fairport's Dave Pegg. Subsequently, Favis-Mortlock played fiddle with guitarist Frank Underwood, and with the Brighton-based folk-punk band Tricks Upon Travellers. He now plays jazz violin, most recently with FiddleBop.
He has published, as of 2012, 30 peer-reviewed articles in professional journals. The most cited have been:
- "Evaluation of field-scale and catchment-scale soil erosion models" by Jetten, V., De Roo, A., Favis-Mortlock, D. 1999 Catena 37 (3-4), pp. 521–541, cited 86 times according to Scopus
- "A self-organizing dynamic systems approach to the simulation of rill initiation and development on hillslopes" by Favis-Mortlock, D. 1998 Computers and Geosciences 24 (4), pp. 353–372, cited 50 times
- "Nonlinear responses of soil erosion to climate change: a modelling study on the UK South Downs " by Favis-Mortlock, D., Boardman, J. 1995 Catena 25 (1-4), pp. 365–387, cited 41 times.
26 papers of his have been cited 26 times or more.
He has also co-edited the book: Modelling Soil Erosion by Water. 
- Favis-Mortlock, David. Use and Abuse of Soil Erosion Models in Southern England. University of Brighton, 1994.
- Boardman, J., Evans, R., Favis-Mortlock, D.T. and Harris, T.M., 1990. Climate change and soil erosion on agricultural land in England and Wales. Land Degradation and Rehabilitation, 2(2): 95-106.
- Favis-Mortlock, D.T., Boardman, J. and Bell, M., 1997. Modelling long-term anthropogenic erosion of a loess cover: South Downs, UK. The Holocene, 7(1): 79-89.
- Favis-Mortlock, D.T., Boardman, J., Parsons, A.J. and Lascelles, B., 2000. Emergence and erosion: a model for rill initiation and development. Hydrological Processes, 14(11-12): 2173-2205.
- Boardman, John, and David Favis-Mortlock. Modelling Soil Erosion by Water. NATO ASI series, vol. 55. Berlin: Springer-Verlag, 1998.