Welch was founding director of Foundation for Ancient Research and Mormon Studies (FARMS) and is the current editor of the periodical BYU Studies. He was director of publications for the Joseph Fielding Smith Institute for Latter-day Saint History. When a young missionary in Germany, Welch discovered many instances of the chiasmus literary form in the Book of Mormon. His finding, published in BYU Studies as "Chiasmus in the Book of Mormon" in 1969 Howard W. Hunter Law Library — Faculty Bibliography Page , and subsequent publications have shaped scholarly inquiry into the linguistic aspects and historical origin of the Book of Mormon.

Welch received his bachelors and masters degree from BYU (B.A. in History, M.A. in Latin and Greek) Two Ancient Roman Plates: Bronze Military Diplomas and Other Sealed Documents. He then studied at Oxford University as a Woodrow Wilson Fellow. DeseretBook.com — John W. Welch BYU Law School Faculty Profile Welch received his J.D. from Duke University. John W. Welch He is the Robert K. Thomas professor of law in the J. Reuben Clark Law School.

In 1979 Welch founded FARMS. He was a member of the board of editors for the Encyclopedia of Mormonism.

Welch was a co-author of Religion and law: Biblical-Judaic and Islamic Perspectives (ISBN 0931464390)