Jardine was born in Oneida County, Idaho, to Rebecca and William Jardine. He graduated with a bachelor of science degree from Utah Agricultural College in Logan, Utah. On September 6, 1905, Jardine married the former Effie Lane Nebeker, they had three children. He attended graduate school at the University of Illinois at Urbana-Champaign in 1906. Jardine had a strong interest in practical farming. He was also attracted to the opportunities in education. He began his teaching in Utah, where he soon became professor of agronomy. In 1910, Jardine moved to Manhattan, Kansas to accept the position of agronomist at the Kansas State Agricultural College. Three years later, Jardine was made dean of the Division of Agriculture and was Director of the Agriculture Experiment Station.
On March 1, 1918, Jardine became the seventh President of KansasState University. He served until February 28, 1925, when he was succeeded by Francis D. Farrell. The office had been vacant after Henry J. Waters resigned to become managing editor of the Weekly Kansas City Star. During his time in office, Jardine penned several handbooks, such as the "Suggestions for Teachers Giving Practical Instruction to City Boys in Care and Handling of Work Horses Care, Adjustment, and Use of Farm Machinery Care and Handling of Dairy Cows and Milk", which was published by the Kansas State Council of Defense. Jardine achieved an outstanding reputation for his work inagricultural education that extended far beyond the borders of the state of Kansas.
On March 5, 1925, President Calvin Coolidge appointed him U.S. Secretary of Agriculture, a position he held for the next four years. In 1926, Jardine played an integral part in the formation of the . After the Chicago Board of Trade adopted his suggestions for regular reporting of the large trader positions, Jardine was the business conduct committee and the formation of a centralized for the clearing house.
At the end of the Coolidge administration on March 4, 1929, Jardine served in President Herbert Hoover's administration as the United States Minister to Egypt from October 13, 1930 until September 5, 1933.
After returning to Kansas in 1933, Jardine became the president of the Municipal University of Wichita. Jardine was appointed by the Kansas State Treasurer from October 2, 1933, and he took the oath the following day. He served in this capacity from October 3, 1933 until 1949.
