Jim received a BSc. (Hons.) in Biochemistry from the University of Edinburgh (UK) in 1996. He stayed on in Edinburgh and was awarded a PhD in Molecular Endocrinology in 2000. His graduate work focused on the molecular mechanisms by which glucocorticoid receptor levels are "programmed" in early life, which has implications for neurodegeneration, diabetes, and other diseases. Jim then took a postdoctoral position at the University of California, San Francisco, where his work, funded by an American Heart Association (AHA) Postdoctoral Fellowship, examined the roles of the serum and glucocorticoid-induced kinases in renal physiology and diabetes.

Jim joined David Ellison's lab in 2005 as a Senior Research Associate. After receiving a K01 from the NIDDK, he transitioned to an independent faculty position in 2011. His current R01-funded work focuses on the regulation of sodium and potassium homeostasis by the Cullin3-WNK-SPAK/OSR1 cascade.