Seiffert was born in Goulburn, New South Wales and was the son of a gardener. He was educated to elementary level and worked as a prison warder. As a youth he was a keen sportsman and was an Australian amateur cycle champion as well as a founder of the New South Wales Country Rugby League. Seiffert was elected as an alderman to Goulburn Municipal Council in 1934–7. Seiffert joined the ALP in 1931.
State parliament
Seiffert was elected to the parliament as the Labor member for Monaro at the 1941 state election. He defeated the incumbent Country Party member William Hedges by less than 200 votes. Monaro was one of a number of rural seats that Labor won at the 1941 election and these victories contributed to the formation of the Labor government of William McKell. Seiffert retained the seat for the Labor Party at the next two elections.
Disendorsement and readmission to Labor Party
In November 1949, Jim Harrison resigned from the Legislative Council to contest the federal seat of Blaxland at the 1949 election. His successor was due to be elected at a joint sitting of the two houses of parliament on 22 March 1950. While the election was by secret ballot, each Labor member of the parliament had a unique how- to-vote card and Labor scrutineers were able to determine if a member had broken caucus solidarity and voted against the endorsed Labor candidate. Very shortly before the election, Sir Asher Joel, a wealthy Sydney businessman, was a surprise nomination against Labor's candidate, Norman Thom. Although Joel lost, he managed to gain 23 votes. Soon it became common knowledge within the Labor Party, although never officially stated, that four members of the ALP had in fact voted for Joel. The four were Seiffert ; James Geraghty of ; Roy Heferen of ; and Fred Stanley of. There were also rumours that all four parliamentarians had received cash payments for their votes, although no such behaviour was ever proven. The state executive of the Labor Party responded by withholding its endorsement for these candidates at the imminent 1950 election. Nevertheless, Seiffert and the other disendorsed members received support from various members of the caucus, and a severe rift developed between the parliamentary and extra-parliamentary parties. This was a major contribution to Labor's poor showing at the election. Seiffert also enjoyed substantial popularity among the members of his own branch, and in fact no alternative ALP candidate from the branch could be found in time. Deciding to defend his seat as an independent, he remained within the ALP on a technicality: because he had not actually stood against a party-endorsed candidate, whereas the other three men had, he was spared the expulsion which the other three suffered. His readmission to the caucus, after the election, gave the government of incumbent Premier James McGirr a one-seat majority in the assembly. He continued to represent Monaro until his death, which took place a few months prior to the 1965 election. Seiffert Oval in Queanbeyan is named after him.
