While studying for his doctorate, Jenkins began working as an assistant chemist for the Connecticut Agricultural Experiment Station in New Haven in 1877, only two years after the Station started. Johnson was the Station's director, while Jenkins and future Storrs Agricultural School principal Henry P. Armsby were his assistants. Jenkins rapidly developed a reputation for both scientific excellence and ability to convince skeptical farmers to adopt new agricultural techniques.[4] He was promoted to vice director of the Station in 1884 and became director in 1900 (when Johnson retired) and treasurer in 1901.