Born on 29 January 1917 as the fourth in a family of six children. Nyholms father, Eric Edward Nyholm (1878–1932) was a railway guard.  Nyholms paternal grandfather, Erik Nyholm (1850–1887) was a coppersmith born in Nykarleby in the Swedish-speaking part of Finland, who migrated to Adelaide in 1873.  Ronald Nyholm valued his Finnish roots and was particularly proud in his election in 1959 as Corresponding Member of the Finnish Chemical Society.
Hailing from the small mining town of Broken Hill, New South Wales, he was early exposed to the role of inorganic chemistry. He attended Burke Ward Public School and Broken Hill High School.  Nyholm married Maureen Richardson of Epping, a suburb of Sydney, NSW, at the parish church in Kensington, London on 6 August 1948.   
After graduating from Broken Hill High School, he attended the University of Sydney (BSc, 1938; MSc, 1942) and then University College London (PhD, 1950, supervised by Sir Christopher Ingold; D.Sc., 1953). On graduation Nyholm became a High School teacher – a contractual requirement of his scholarship to university.