Underwood earned degrees from Freed-Hardeman College, Harding College and Harding Graduate School of Religion.
He began his preaching ministry at age 20. He ministered throughout the U.S. and held full-time preaching positions in Comanche, Okla., Germantown, Tenn., and Sheffield, Ala.
He served as a missionary throughout the Caribbean and in West Africa and served as an elder at Chisholm Hills Church of Christ in Florence, AL for 25 years. Underwood was also Professor of Bible at Heritage Christian University for 35 years.
He was preceded in death by his parents and eldest sister, Juanita Higdon Crowley. He is survived by his beloved wife of 59 years, Myra Wade Underwood; daughter, Rebecca Dorfmueller; sons, David Underwood and Bryan Underwood; six grandchildren, Matthew Underwood, Luke Underwood, David Andy Dorfmueller (Sgt., U.S. Army), Susanna Dorfmueller, Brody Underwood and Aubree Underwood; one great-grandson, Roshaun Rogers; two sisters, Lois Stephens and Carolyn Minor Barnett.
Underwood was buried in a private service on Feb. 15, with a memorial service open to the public at the Chisholm Hills church.
Mr. Underwood had requested, in lieu of flowers, that donations be made to Heritage Christian University in Florence.