Joshua Reuben Clark, Jr., was born in a rock house built by his father about three miles north of Grantsville, Tooele County, Utah, on 1 September 1871. His father, born and reared in Indiana, was a Union soldier in the Civil War, came West, mined in Montana, and was converted to "Mormonism" soon after arriving in Salt Lake City. His mother was born in an overnight camp of Mormon pioneers in what is now Keith County, Nebraska. She was a daughter of Edwin D. Woolley, who was a friend of the Prophet Joseph Smith and later bishop of a Salt Lake City ward for twenty-eight years.
Young Reuben was the eldest of the children, and, being reared in a rugged pioneer environment under austere conditions, was given many responsibilities very early in life. Simultaneously his physical and moral stamina began to manifest themselves. Even as a youth his was the life of a participant and not merely that of a spectator. He was actively involved in the Church programs in his community: attending meetings, giving recitations and talks, holding office appropriate to his age, making contributions to the poor, and accepting labor and other assignments in which he could render service. He also developed an appreciation for and some personal skills in both music and drama as he faithfully used his talents in those arts throughout the years of his youth.