McCary served in both houses of the Alabama State Legislature but the dates are uncertain, based on the newspaper stories at the time of his 1981 death. McCary ran unsuccessfully for Lieutenant Governor of Alabama in 1946; the office was won instead by another Democrat, James C. Inzer. McCary attributed his switch in parties to the need for a combination of political reform and the establishment of a two-party system in his native state. Forrest French, a former Calhoun County Republican chairman, described McCary, accordingly, as "frank, full of candor, and we agreed in the party approach to politics.... He constituted the framework that was in existence even in the lean times." After his race against Wallace in which he polled less than 15 percent of the ballots cast, McCary said that despite his expected defeat, he believed that he had "accomplished my purpose. And I think the only hope for the Republican Party at the state level is to offer the voters a choice for all offices in all elections." Though the Alabama GOP had offered no nominee against George Wallace in either 1962 or 1970, it had fielded then U.S. Representative James D. Martin of Alabama's 7th congressional district in the 1966 general election against Wallace's first wife and political stand-in, Lurleen Wallace. At that time, Alabama governors could not succeed themselves. McCary was a close friend of Democrat James B. Allen, a two-term lieutenant governor who was elected in 1968 to the United States Senate. Allen supported Wallace in 1974; Wallace subsequently appointed Allen's second wife, Maryon Pittman Allen, to fill the remaining months of Allen's term after the senator's unexpected death on June 1, 1978. McCary ran in the special election to choose Allen's successor for a two-year term but was defeated, 72-28 percent, by intraparty rival, George W. Nichols. Nichols then withdrew from the contest, and James D. Martin of Gadsden replaced him as the nominee; Martin lost, 55-43 percent, to Democrat Donald W. Stewart of Anniston, who had defeated Maryon Allen in the special Democratic primary. After years of political failure, McCary lived to see a Republican breakthrough in Alabama in 1980 with the victories of Ronald Reagan as U.S. President and retired AdmiralJeremiah Denton to the same U.S. Senate seat earlier filled by Allen and sought by McCary.
Personal life
About 1960, at the age of fifty-three, McCary wed the former Margaret Pauline Waters, a native of Detroit, Michigan, who moved to Alabama for her senior year of high school. From 1943 until their divorce in 1959, she was married to James Dillard Sloan, Sr., the father of McCary's stepson, Anniston lawyer and former Circuit Judge James D. Sloan, Jr.. McCary had two daughters, from a previous marriage, Eileen M. Cline, formerly of Troy, Virginia, and from the second marriage, Anne Margaret McCary Childers of Gadsden. Anne Childers is the widow of Ted Childers and the mother of three children. McCary was affiliated with the Episcopal Church of St. Michael and All Angels in Anniston. He is interred at Edgemont Cemetery in Anniston.