His mother was a qualified teacher, and his father was a surveyor with interests in geophysics and astronomy, who later changed his career to become involved in geodetic computing.

Describing his childhood in an interview, he said that he "came from a middle class family with lots of books in the house and parents who were very keen on [him] learning to play the piano."

He qualified for a British Commonwealth Scholarship and moved to Canberra, Australia, where he studied for his PhD in astrophysics at the Australian National University's (ANU's) Mount Stromlo and Siding Spring Observatories.

[6] In 1982, having received his doctorate, Couch moved to the University of Durham in England, where he worked as a postdoctoral fellow in the observational cosmology group.

[9] Over this period the advent of CCD imaging cameras on the AAT, with their greatly superior sensitivity, provided much more detailed information on distant galaxy clusters than was possible with the previous two-colour photographic approach.

Couch exploited this opportunity to provide a clear picture of what the different spectral signatures told us about the underlying patterns of star formation activity.

[3][19] He explained his motivation for making the change in an interview, saying that "wanting to do things to advance research is very, very difficult in a big university where there are many more groups competing for money".

[20] While there, he was instrumental in forging a deal which allowed Swinburne astronomers access to the twin ten-metre Keck telescopes in Hawaii.

In announcing the appointment, the Minister for Science and Research, Senator Chris Evans, described Couch as "one of Australia's leading astronomers and cosmologists".

One of his most pressing priorities in taking up this role was to assist the Australian National University with the recovery of the Siding Spring Observatory (which hosts the AAO telescopes) following the January 2013 bushfires.

He was also a lead investigator on the AAOmega "WiggleZ" Project, which provided some of the key evidence showing that the expansion of the universe is accelerating, driven by the previously unknown dark energy.

Something, which has been called dark energy, is driving that because the most common force that controls motions in the universe, gravity, would cause things to slow down not speed up.

The team of twenty researchers using the 3.9-metre AAT and also working with collaborators in Toronto, Canada and at the California Institute of Technology and the Jet Propulsion Laboratory in the US.

[13][30] His study to determine the morphologies of galaxies in distant clusters, using data from images derived from the pre-refurbished Hubble Space Telescope, was used as the basis for the MORPHS collaboration.

[36] On the occasion of the award of an honorary Doctor of Science at Victoria University of Wellington, New Zealand in May 2012, the vice-chancellor Professor Pat Walsh highlighted that Couch is in the top ½% of his field as a high-citation researcher.