[2] Katz led successful strikes in Hobart and Launceston, but enthusiasm later declined and he resigned his positions in January 1914 in order to return to Melbourne.

He was an opponent of conscription, and in 1915 he successful moved that the Melbourne Trades Hall ignore correspondence sent by the Federal Parliamentary War Committee.

As a result of that, and likely also due to his German background, he was publicly tarred and feathered in December 1915 by several men in military uniform, outside his office in Little Collins Street.

During World War II, he represented the unions on the Cargo Control Committee, and was a deputy member of the Victorian Industrial Court of Appeals.

[1] Katz rescinded his earlier opposition to the ALP after World War I and served on the state executive for a number of years.

By the time he reached the Senate he had become an anti-communist, although he opposed the Menzies Government's attempts to ban the Communist Party of Australia as he believed they were counter-productive.