Björn joined Weill Cornell Medical College in 2015 as an Assistant Professor in the Department of Microbiology and Immunology. He received his doctoral training at Johns Hopkins University and the University of Michigan investigating how proteins secreted by the intracellular parasite Toxoplasma gondii allow it enter and exit host cells.

As a postdoctoral fellow at Princeton University, Björn explored the molecular underpinnings of how malaria parasites initiate the development of its sexual stages, a process critical for their transmission to the mosquito. He was a student in the Biology of Parasitism course in 2004.