Donald has been employed by Edinburgh University since 1981, as a Research Fellow, Lecturer, Reader and, since 1998, as Professor of Computer Science in the Division (now School) of Informatics.

His research interests include functional languages (development of HOPE and Standard ML), algebraic specification languages (CLEAR, ASL, Extended ML, CASL), mechanised reasoning, foundations for algebraic specification and formal software development, and applying these foundations to the practical development of modular software systems from specifications.

He has published about 50 papers in journals and international conferences and has held a series of grants since 1985 for research projects in the area of verification and formal development of programs. He is currently the overall coordinator of CoFI, the Common Framework Initiative for algebraic specification and development of software, and of the ESPRIT-funded CoFI working group. He has served on the programme committee of 17 international conferences, was programme chair of ESOP'94 and conference chair of CAAP/ESOP/CC'94 in Edinburgh, and is chairman of the steering committee for the ETAPS conference. He is on the editorial board of the journals Theoretical Computer Science and Electronic Notes in Theoretical Computer Science and is a member of the Council of the European Association for Theoretical Computer Science.

A dozen Ph.D. theses have been completed under his supervision; two of these won the British Computer Society's prestigious Distinguished Dissertation award. From 1996 to 1999 he was Director of LFCS and he is a founding member of IFIP WG1.3 "Foundations of System Specification".