MRCS LRCP 1891; MB ChB Manch 1893; FRCS Eng 1894; MB BS Lond 1893, MD 1894.
Clegg studied at Manchester where he had a distinguished academic career. Clegg decided to specialise in diseases of the eye, and held a resident post at Manchester Royal Eye Hospital, where he later became consultant. At the Royal Eye Hospital, Clegg was at the forefront of contemporary knowledge and was eager to put into practice new methods of treatment. Clegg was also on the honorary staff of MRI from 1918 until 1924 and lectured in ophthalmology at the University. Clegg was a leading authority on ophthalmology, being a pioneer in the treatment of glaucoma, detachment of the retina and training for squint cases. Clegg retired in 1938 and died in Epsom, Surrey in 1941. Clegg was a founding member of the North of England Ophthalmological Society and was president of Manchester Medical Society .