He served in the Royal Air Force during World War II, then resumed his legal practice and took silk in 1949.
[1] In 1964, he was appointed as Solicitor General for Scotland in Harold Wilson's first government.
[2] He held that post until the following year, when he was appointed as a judge to the College of Justice, replacing Charles Shaw, Baron Kilbrandon.
[3] He was cautious when hearing trials, and deferred to other judges in appeal cases.
[4] Leechman retired from the judiciary in 1976, and then edited some of his session cases.