Professor Johnston completed his undergraduate degree at St. John's College in Santa Fe, NM, in a program emphasizing discussion-based classes with a focus on source texts in western philosophy, literature, and history of math and science.  His Ph.D. in Mathematics is from Western Michigan University where he studied Graph Theory with Ping Zhang.  Before coming to Trinity College, he most recently held a similar position at Skidmore College.  He is excited about meeting the students here and finding the right balance of in-class activities and interactive lectures as he teaches classes across the mathematics curriculum.

• Deranged matchings: proofs and conjectures (with P.M. Kayll and C. Palmer). The American Mathematical Monthly. 131 (2) (2024), 95–111.
• Rainbow saturation (with N. Bushaw and P. Rombach). Graphs and Combinatorics. 38, 166 (2022).
• Lower bounds for rainbow Turan numbers of paths and other trees (with P. Rombach). Australasian Journal of Combinatorics. 78(1) (2020), 61-72.
• On edge-colored saturation problems (with M. Ferrara, S. Loeb, F. Pfender, A. Shulte, H. Smith, E. Sullivan, M. Tait, and C. Thompkins). Journal of Combinatorics. 11(4) (2020), 639–655.
• Rainbow Turan problems for paths and forests of stars (with C. Palmer and A. Sarkar). Electronic Journal of Combinatorics. 24(1) (2017), #P34.
• On twin edge colorings of graphs (with E. Andrews, L. Helenius, J. VerWys and P. Zhang). Discussiones Mathematicae Graph Theory. 34 (2014), 613-627.