McClelland is thought to have been born in Ireland, studied medicine and was admitted member of the Royal College of Surgeons in 1828.
[4][5] At the time he was deputy apothecary, assistant opium examiner as well as secretary to the coal and iron committee with the first position requiring his presence in office from eleven to four daily.
McClelland quit the Asiatic Society of Bengal and founded and edited the Calcutta Journal of Natural History, and Miscellany of the Arts and Sciences in India which ran from 1841 to 1847.
McClelland's major botanical contribution was his editing of the work of William Griffith which was published posthumously as Notulae ad plantas asiaticas.
[10] McClelland is commemorated in the name of the mountain bulbul, Ixos mcclellandii and a species of snake, Sinomicrurus macclellandi.