When John Calvin Mast was born on 20 August 1860, in Laurel Creek Township, Watauga, North Carolina, United States, his father, Eli J Mast, was 46 and his mother, Celia Callie Dugger, was 35. He married Martha Evelyn Trivette in 1883, in Oregon, Lincoln, Tennessee, United States. They were the parents of at least 1 son and 5 daughters. He died on 4 April 1945, in Laurel Creek Township, Watauga, North Carolina, United States, at the age of 84, and was buried in Mast Cemetery, Rominger, Watauga, North Carolina, United States.