He was a prominent barrister based in Brisbane and also served as a judge-advocate in the Royal Australian Naval Volunteer Reserve.

[3] In 1989, Cooke was appointed by the Queensland state government led by National Party premier Mike Ahern to inquire into alleged corruption and misconduct in trade unions.

[5] The Cooke Inquiry was later assessed as a "transparent attempt to shift the focus away from Fitzgerald's findings about the government and onto allegations concerning Labor Party–linked unions".

After Ahern lost the 1989 state election, the new Labor Party premier Wayne Goss reduced the resources and funding available to the inquiry[6] Goss was later openly critical of Cooke's conduct of the inquiry and stated he had only discovered "a bit of corruption in two unions" at a cost of over $6 million.

In the aftermath of the Sandline affair he appeared for PNG prime minister Julius Chan and his deputy Chris Haiveta in the commission of inquiry.

He appeared as an advocate in military tribunals, courts-martials and inquiries, and later served as a judge-advocate and defence force magistrate.

[11] The Canberra Times reported that he had alienated Liberal Party officials by, among other things, opting for a silent telephone number.