This early access to technology ignited Schnell's interest for using mathematical approaches to solve complex problems and laid the foundation for his future work in scientific research.

He pursued his doctoral and postdoctoral research under the supervision of Philip Maini, FRS in the Wolfson Centre for Mathematical Biology at the University of Oxford.

[7] Schnell has also focused his research attention on deriving mathematical expressions to estimate enzyme kinetics parameters under different reaction conditions.

He has systematically obtained equations to estimate kinetic parameters for the family of Michaelis-Menten reaction mechanisms and determined their region of validity for the initial enzyme and substrate concentrations.

Schnell derived a generic expression, known nowadays as the Schnell-Mendoza equation,[8] to determine the Michaelis constant and maximum velocity for enzyme catalyzed reactions following Michaelis-Menten kinetics using time course data.

His work has been highlighted in popular science magazines, such as American Scientist[10] (USA), Investigación y Ciencia[11] (Spain and Latin-America), Spektrum der Wissenschaft (Germany).

[17] Schnell is an elected Fellow of the American Association for the Advancement of Science for distinguished contributions to the field of mathematical biology, particularly for the theoretical modeling of complex biochemical reactions and optimal estimation of their rates.

[19] The Society for Advancement of Chicanos and Native Americans in Science conferred upon him the 2023 SACNAS Distinguished Scientist Award in recognition of his significant contributions to enzyme kinetics and the creation of a fundamental quantitative enzymological model of the Polymerase Chain Reaction.

As an educator, Schnell co-organized the establishment of a summer fellowship program to attract undergraduate students to gain hands-on research experiences in the department.

In the fall of 2021, the College of Science launched the first minor program in the country focusing on rare disease patient advocacy.

[32] During his tenure, the University of Notre Dame receive a $20 million gift to endow the newly established Berthiaume Institute for Precision Health.

[33] He contributed to the expansion of the University of Notre Dame East Campus Research Complex with the addition of a 200,000-square-foot science and engineering building.

A series of ongoing health challenges in Schnell's life has prompted him to channel his research endeavors into the field of biomedical sciences.