In 1837, a year after the Wallaces were married, David was elected the sixth governor of Indiana, He served from December 6, 1837, to December 9, 1840, and Zerelda, who was in her early twenties, became First Lady of Indiana. In 1841 David served a one-year term in the U.S. Congress, but failed to win re-election and returned to his Indianapolis law practice in 1842. He was judge of the court of common pleas for Marion County, Indiana, until his death in Indianapolis on September 4, 1859. After David's death, Zerelda was left nearly penniless with young children still at home, but she refused assistance from other family members. Fortunately, she retained the family's residence in Indianapolis and took in boarders to earn an income. In 1870 she took on the additional task of caring for the four children of her daughter, Mary, who had died in childbirth.