After leaving the navy, McFarland returned to Oklahoma for a short time before he decided to move to
Arizona. He arrived in
Phoenix on May 10, 1919, and after several days found employment at a local bank. Seeing little opportunity for advancement at the bank, he applied to the
Stanford University Law School. Before leaving to begin classes, he filed for a
homestead near
Casa Grande. McFarland would later refer to the land as his "
jackrabbit farm". McFarland attended law school for four quarters before he took a break. His parents and younger brother had moved to Arizona. At the time, Stanford recommended all law students to spend a quarter
interning at a legal office. Feeling homesick after a year in
California, McFarland worked at the Phoenix office of Phillips, Cox, and Phillips. He was legal clerk for future Arizona Governor
John Calhoun Phillips. McFarland was also introduced to a variety of figures within the Arizona political establishment. At the completion of his internship, he returned to Stanford. McFarland completed work on his
Juris Doctor in the summer quarter in 1922. In addition, he had completed the class work for a
Masters of Arts degree in
political science. McFarland was admitted to the Arizona Bar later that year. Upon graduation from law school, McFarland moved to Casa Grande to "prove up" his homestead claim and open his first legal practice. The Arizona economy was doing poorly, and he found little legal work. He dealt with the lack of work by becoming involved in politics. McFarland worked for
George W. P. Hunt's campaign during the
1922 governor's race. After Hunt won the election, McFarland received an appointment as assistant
attorney general. In mid-1924, he returned to Stanford to complete work on his master's degree. Later that year he was elected
county attorney for
Pinal County. As state law required the county attorney to reside in the
county seat, McFarland moved to
Florence. He served three two-year terms in that position. McFarland married Clair Collins on January 1, 1926. The couple had initially met at a Christmas party at Stanford in 1919. They had corresponded after their initial meeting, and by the time McFarland was elected, Collins was working as a teacher at Florence high school. The couple had a son, William Ernest, in 1927 and a daughter, Jean Clair, in February 1929. William became ill and died several days before his sister's birth, and Jean died two days after her birth. McFarland's wife suffered from depression following the loss of their two children. She showed signs of improvement in 1930 as the couple expected a third child. The third child, Juliette, was
stillborn, and Clare McFarland developed
postpartum complications, which led to her death on December 12, 1930. By February 1930, McFarland represented the state during
Eva Dugan's final appeal before her execution, a task that he found very unpleasant. Shortly afterwards, he decided that he was tired of being a prosecutor. Instead, McFarland ran for a seat on the
Superior Court in Pinal County but lost the race to the incumbent, Judge E. L. Green, by 1464 to 1358. Upon leaving office as county attorney, McFarland joined with his chief assistant, Tom Fulbright, to found the law office of McFarland and Fulbright. The practice gained public recognition when McFarland won an appeal that determined
Winnie Ruth Judd to be insane, but its primary area of effort was
water law. Despite the success of his legal practice, McFarland still wished to become a judge. He ran a second time in 1934, defeated E. L. Green 2543 to 1542 in the
primary, and was unopposed in the
general election. In 1935, McFarland was sworn in, and he sat on the bench for the next six years. As his workload in Pinal County was light, he accepted cases from other parts of the state, which allowed him to sit on the bench in every county in the state and to gain experience in issues in all parts of the state. As a judge, his rulings were well respected, and he was overturned on appeal only three times. While on the bench, McFarland became romantically involved with a widow, Edna Eveland Smith, who had a young daughter, Jewell. She taught history and mathematics at Florence High School until the couple married in
Tucson on June 1, 1939. McFarland also adopted his wife's daughter. ==US Senator==