In 1953, after becoming a judge, Amsberg was appointed as a Commissioner to preside over the highly political Royal Commission of Inquiry into the conduct of Joshua Arthur, a New South Wales government minister.

[9][12] Described as "one of the leaders of the junior Bar before he joined the Navy", Amsberg's accommodation was initially sub-standard, having to interview clients and solicitors in a very small room on the premises.

[13] In the late 1940s and early 1950s Amsberg took on well-known Sydney criminals as clients, including John 'Chow' Hayes and William 'Joey' Hollebone, defending them in a number of high-profile cases.

[15] In March 1953 Amsberg was appointed as sole commissioner to conduct the Royal Commission to inquire into and report upon whether Joshua Arthur, a New South Wales Government minister, "acted corruptly or improperly in any association or dealing" with Reginald Doyle (and other related matters).

[17] From about June 1953 Amsberg regularly appeared as a 'Brains Trust' panellist, public events organised by the YMHA (Young Men's Hebrew Association) and through the Temple Emanuel.

Brains Trust events involved an expert panel with diverse backgrounds assembled to answer questions previously submitted by members of the public.

His obituary in the Australian Law Journal concluded with the following words: "He will always be remembered as one of the most colourful legal personalities of his time in Sydney, and for his kindness, friendliness and generosity on all occasions".