Greg Parker was born in Newcastle, NSW, Australia in 1958. Having been to 11 different schools, he left altogether at age 14, bumming around the country doing odd jobs until joining the Public Service in 1988. By 1995, he found himself living in tropical Darwin, where he still resides. Greg Parker left the Public Service in 1999, and is currently the manager of the largest employment agency in the city.

Greg Parker's interest in the assassination started, as it did with so many others, after watching Oliver Stone's JFK.

That interest was short-lived, but rekindled in the late 1990s after reading a borrowed copy of Conspiracy by Anthony Summers. He began his own research in 2000, and since then, has contributed to Joan Mellen's book on Jim Garrison. Greg Parker also had some of his research presented at the Pittsburgh conference in November, 2003. This included strong evidence showing Jack Ruby to be a conduit for funding WMD research in the late 1950s, and the role played by John Edward Pic Jr in USAF human radiation experiments.

Greg Parker runs the Re-open the JFK Case website.