Club football In 1970, Hillis became the team doctor for
Clydebank and remained in this position for 27 years. He had a brief spell as club doctor at
Rangers F.C. but during this period the club signed
Daniel Prodan in 1998 without some significant medical problems being discovered before the completion of the deal. When the club's owner
David Murray rushed the deal for the player through, Hillis hadn't been allowed the normal amount of time to complete his medical checks.
International football In 1976, he began working with the
Scottish Football Association to provide medical support for the
Scotland national under-21 football team and he covered 54 matches. In 1985, at the
Wales vs Scotland football match in
Cardiff, the Scotland team manager
Jock Stein collapsed and although Hillis and the team attempted resuscitation, Stein died from a heart attack. Hillis helped establish the Sports Medicine Centre inside
Hampden Park, the first of its kind in a national stadium. He stepped down as the Scotland team doctor in 2010, but remained involved research and he continued to be involved with the SFA. He became the medical director of the SFA. In 1986, he became a member of UEFA's Medical Committee He was a medical adviser to FIFA.
Commonwealth Games Hillis had been working with the medical team to prepare for the
2014 Commonwealth Games. He was diagnosed with mesothelioma in May 2014, however he continued to work until the middle of June. ==Awards and honours==