The early history of David in Unknown. David married Margaret Minerva Andrews in 1839 in Hillsborough, North Carolina. In 1843, David and Margaret were taught by Missionaries from the Church of Jesus Christ of Latter-day Saints. David and Margaret were converted, and David was baptized on May 15, 1843.
After his time in the Mormon Battalion, David made his way to the Salt Lake Valley on Oct 16, 1847. He traveled back to Winter Quarters, Iowa, from the valley and retrieved Margaret. The Rainey's lived in Winter Quarters until they had the means to travel to Utah. They joined the Philemon C. Merrill Company on June 5, 1856 and arrived in the Salt Lake Valley on Aug 13.
During their travel, Margaret, who was a frail woman from birth, had difficulty crossing the plains and participating in regular pioneering life. The Rainey family moved to Provo after their arrival, where Margaret's condition continued to worsen. Provo citizen Dorothy Jane Dennis was appointed as a nurse for Margaret, but she was not improving. Margaret died on Feb 21, 1857 in Provo. Just before her death, she told David to marry Dorothy. David and Dorothy were married on Feb 9, 1857 in a non-polygamous relationship.
In 1858, David was called to serve as Bishop of Salem, Utah. He served as Bishop until 1860 when the Rainey's were called to move to Cache Valley and settle the area. The Raineys chose to live in Richmond.