Sandison obtained a master's degree in 1991 and a PhD in 1994, both from the University of Cambridge.
It was announced on 4 February 2021 that Sandison had been appointed as a Senator of the College of Justice.
[1] He was installed as a Senator of the College of Justice at a ceremony in the Court of Session on 23 February 2021, taking the judicial title of Lord Sandison.
[2] Sandison acted for Wings Over Scotland blogger Stuart Campbell in his defamation action against former Scottish Labour leader and Member of the Scottish Parliament Kezia Dugdale, over a newspaper column she had written.
[3] This was the first case to ever be heard by the Inner House of the Court of Session virtually and was done so in the wake of the widespread restrictions imposed in response to the COVID-19 pandemic.