On 1 September 2016, Mullholland was appointed as a temporary judge of the Court of Session, to fill the gap caused by Lady Smith's appointment as chair to the Scottish Child Abuse Inquiry. The Judicial Office for Scotland announced that "Judge Mulholland will not hear any criminal case in which, by reason of his previous role as Lord Advocate and head of the prosecution service, he would require to recuse himself; nor any civil case involving the Scottish government which, given his former role as the Scottish government’s principal legal adviser, he would again need to recuse himself. The requirement for Judge Mulholland to recuse himself will, of course, diminish over time."