Leo Preston Vernon was born on October 10, 1925 in Roosevelt, Utah to William Morley Vernon and Roseltha Bingham. As a child he lived in briefly in Kanab, Utah, before the family settled in Orem, Utah, where he was raised. After high school he studied chemistry at Brigham Young University (BYU). In 1944, he joined the United States Army, and was trained as an X-ray technician. However, he spent most of his time in the service as a member of music corps. In 1946 Vernon returned to BYU and completed his degree in chemistry in 1948. That year he also married Fern Trunkey in Salt Lake Temple, and they later had five children. Vernon completed his education earning a Ph.D. in biochemistry at Iowa State University, and doing post-doctoral research in Madison, Wisconsin and Washington University of St. Louis.

Vernon joined the BYU chemistry faculty in 1954, but left for a year's study at Nobel Institute in Stockholm, Sweden in 1960. After his fellowship he did not return to the university, instead becoming the director of Kettering Research Labs in Yellow Springs, Ohio, from 1961 to 1971. In 1971, he was recruited by university president Dallin H. Oaks to return as director of Research Division at BYU. In 1974, he was advanced to the role of Assistant Academic Vice President. At the end of the Oaks administration he returned to the Chemistry Department, where he taught for five years. Vernon retired from BYU in 1991.

In addition to his academic work, Vernon served as a bishop, high councilor, stake presidency member, and stake president for the Church of Jesus Christ of Latter-day Saints.

The Department of Chemistry was established and made a department within the School of Arts and Sciences in 1920 when the Church Teachers College was split. In 1921 the department became part of the College of Arts and Sciences and was later transferred to the College of Physical and Engineering Sciences in 1954. In 1973, the department was moved into the College of Physical and Mathematical Sciences. The department was disbanded in 1995 to form the Department of Chemistry and Biochemistry. Department chairs included Charles E. Maw (1920-1945), Joseph K. Nicholes (1946-1956), H. Smith Broadbent (1955-1958), Keith P. Anderson (1958-1960); and Albert D. Swenson (1960-1964).