Gavin was born in Newport, Wales and read Chemistry with Medicinal Chemistry at UMIST where he was awarded an MChem in Medicinal Chemistry. Continuing his studies at the University of Manchester, Gavin undertook a PhD in synthetic carbohydrate chemistry, investigating multivalency, followed by a PDRA at St Andrews University (with Professor S. J. Conway). Gavin then worked in industry, firstly at Ferring Pharmaceuticals, on the design of new treatments for primary dysmenorrhea and secondly at Peakdale Molecular on the design of an anti-nicotine vaccine.

Gavin returned to academia and the University of Manchester in 2010, firstly as a PDRA in the Manchester Institute of Biotechnology developing chemical synthesis approaches to heparan sulfate oligosaccharides (with Dr J. M Gardiner) and secondly as a fixed-term lecturer, in 2014, within the School of Chemistry. He took up a Lectureship in Organic Chemistry at Keele in 2016 and was promoted through the ranks to Professor of Biological Chemistry in 2021. From 2025 he returned to the Manchester Institute of Biotechnology and Department of Chemistry at the University of Manchester as Professor of Chemical Biology.