McLachlan was born on 2 November 1872 in Naracoorte, South Australia. He was the son of Mary (née Patterson) and Alexander McLachlan. His parents were Scottish immigrants from the Western Highlands and spoke Scottish Gaelic.[1] His mother "read the Gaelic Bible to him each night and taught him Gaelic songs".[2]
McLachlan was raised on his father's sheep-farming property at Naracoorte and received his early education at home. He later attended Hamilton Academy, a private school in Hamilton, Victoria, before completing his secondary education at Mount Gambier High School. McLachlan went on to study law as an articled clerk, initially with Davison and Daniel in Mount Gambier from 1890 and then with Eustace B. Grundy's firm in Adelaide.[2] He completed a certificate in law at the University of Adelaide and was called to the South Australian Bar in 1895.[1]
In 1895, McLachlan established a legal practice in Gladstone, moving to Petersburg in the same year.[1] He developed a friendship with South Australian premier Charles Kingston and in 1897 moved to Adelaide to become a partner in Kingston's firm. Due to Kingston's political obligations he took on the majority of the firm's work.[1] Their partnership ended in 1905 and McLachlan subsequently took on several other partners, including Mellis Napier.[2]
McLachlan was one of the founders of the Liberal Union in 1910, a merger of local liberal organisations. He succeeded Joseph Vardon as president of the party in 1913,[2] serving until 1916. He was later involved with the eventual merger of the Liberal Union and the National Party to form the new Liberal Federation in 1923.[1]
McLachlan became an outspoken advocate of military preparedness and supported sanctions against Italy in response to its invasion of Ethiopia, antagonising cabinet. He also pressed Lyons over his unwillingness to put into place the provisions of the National Health and Pensions Insurance Act 1938. On 3 November 1938, McLachlan was questioned in parliament over the letting of a contract by the Postmaster-General's Department to the Hume Pipe Co. Lyons' lukewarm defence caused McLachlan to resign as Postmaster-General the same day.[1]
McLachlan remained on the backbench following his resignation from cabinet. During World War II he was chairman of the Joint Committee on War Expenditure from 1941 to 1944 and also served on the Regulations and Ordinances Committee.[2] He unsuccessfully sought Liberal and Country League preselection for a further Senate term prior to the 1943 federal election, but recorded only eight out of 200 votes from preselectors. His final Senate term expired on 30 June 1944.[2]
Personal life
In 1898, McLachlan married Cecia Antoinette Billiet; the couple had no children.[1] They lived in Melbourne from the late 1920s, also acquiring a small grazing property near South Morang.[2] He was widowed in 1941 and died on 28 May 1956 at the Mercy Hospital in East Melbourne.[1] His estate was valued for probate at £128,160 (equivalent to $4,700,000 in 2022) and was divided between three nephews.[7]
McLachlan played golf, bridge and billiards and was interested in horse racing. He was chairman of the South Australian Football League from 1920 to 1925. He was also a "connoisseur of antiques and had a fine collection of silver".[2] In 1948 he published an autobiography titled McLachlan: An F.A.Q. Australian.[1]
