He earned a Bachelor of Science in Agriculture with first-class honours from the University of Sydney in 1964, followed in 1968 by a Ph.D. in animal genetics from the same institution, supervised by J. Stuart F.

They identified lack of gene flow in fragmented populations and lack of remedial management actions as one of the most important, largely unaddressed problems in conservation biology,[25] identified the primary cause of this problems as fears that crossing populations would be harmful (outbreeding depression),[18] devised a procedure to estimate the risk of outbreeding depression,[18] showed it worked, showed that outcrossing typically leads to large benefits in reproduction and survival,[26] and advocated for a paradigm shift in genetic management of fragmented populations.

[4][5][27] Frankham's team provided the experimental test in a living organism of what is now the recommended genetic management procedure for threatened species (minimizing mean kinship).

[28][29] From 2020 to 2023, Frankham has been involved in attempts to strengthen the genetic content of the Convention on Biodiversity through committee work and publications.

[31] With collaborators, he then discussed the evolution of global biodiversity framework (GBF) and recommended several measures to improve it in order to conserve genetic diversity.