In 1995, Hamilton was appointed a Senator of the College of Justice with the judicial title, Lord Hamilton. Although titled 'Lord', he is not a peer; akin to the honorific title bestowed on the younger sons of Dukes and Marquesses who are also not peers. Between 1997 and 2000, he was a full-time commercial judge dedicated to commercial business and responsible for oversight of that aspect of Court of Session business. In January 2002, he was appointed as a Judge of the Inner House of the Court of Session where he sat principally on appellate business.