In 1972, Dr. Kropinski started on an academic track in the Department of Microbiology and Immunology (currently Department of Biomedical and Molecular Sciences) at Queen's University (Kingston, Ontario) - a career which lasted 32 years. During this time, his work examined lipopolysaccharide biosynthesis in Pseudomonas aeruginosa, lysogenic conversion, development of shuttle vector systems, and cytochemistry of the sheath of the saprophytic spirochete, Spirochaeta aurantia. Sabbatical leave in 2004 resulted in a career change to a Government of Canada research scientist with the Public Health Agency of Canada's Laboratory for Foodborne Zoonoses (Guelph, Ontario) where his research centred on the development of a molecular typing system for Salmonella leading to the genome sequencing of several hundred Salmonella strains. In 2014, Dr. Kropinski "retired" for the second time, and took up two adjunct positions at the University of Guelph. As a consulting virologist, he now works on analyzing the genomes of bacteria and phage for students, their supervisors, and NCBI.

In his spare time, he is bringing order to the burgeoning chaos of bacteriophage classification through his role in the Bacterial Viruses Subcommittee of the International Committee on Taxonomy of Viruses. He tells us that the only constants in his life are a love for problem-solving, bacteriophages, and his partner in the adventure of life, Peggy Pritchard, the author/editor of "Success Strategies from Women in STEM: A Portable Mentor."