Representing his father's former electorate, Hermann Homburg served as a non-Labor Party member for Murray in the House of Assembly from 1906 to 1915. He became Attorney-General under Premier Archibald Peake in 1909 and also Minister for Industry from 1912 to 1915. The outbreak of World War I in 1914 resulted in widespread distrust and persecution of German-Australians. In 1914, while he was Attorney-General, Homburg's government office in Adelaide was raided by soldiers with fixed bayonets. He soon fell victim to anti-German sentiment and resigned in early 1915 to avoid embarrassing the government in the forthcoming election. Homburg wrote of a "campaign of lies and calumnies against me... because I am not of British lineage."
Between the wars
In 1927, Homburg successfully contested Murray again and returned to parliament. He served as Attorney-General and Minister for Industry in the R. L. Butler ministry from 1927 until losing his seat in 1930. From 1933 to 1941 he was a member of the Legislative Council. He was also a leader of Adelaide's secular German community during the interwar period. Despite his many years of public service, Homburg's loyalties were once again questioned following the advent of World War II. His home and private office were searched and he was interned on 25 November 1940 but released after appeal on 21 December, under open conditional arrest, one condition being that he moved interstate. In January 1941 he relocated to Melbourne and then moved to Ballarat whereupon he retired from parliament. The judges at Homburg's appeal concluded, "it is obvious that one or more of the persons reporting may have a grudge against the objector Homburg and under pledge of secrecy be willing to lie to cause him distress and trouble."
After politics
Homburg returned to Adelaide in 1942 and continued to practice as a solicitor until his death in 1964. He wrote about his experiences during both wars in South Australian Lutherans and War-Time Rumours. In 1945 Homburg was identified "holding a celebration on Hitler's birthday" at a cafe in Adelaide. This was after the horrors of Auschwitz became public knowledge. The Chronicle newspaper reported the event: "One Adelaide man, who saw members of the party entering the cafe about 3.50 p.m. on Friday, said that he was astounded to think such an assembly could take place in the heart of the city... "I remarked to a friend that with the atrocities in Europe now being revealed, it was just as well none of our servicemen were present to see what was taking place."
