Mark Brennan (also referred to as just Brennan) is a fictional character from the Australian soap opera Neighbours, played by Scott McGregor. He made his first appearance during the episode broadcast on 30 August 2010. McGregor initially had a four-week guest contract, but this was increased to six months. Shortly after, it was announced that McGregor's contract had been extended again to twelve months and that he would become a regular cast member. McGregor departed the serial on 22 June 2011, after his contract was not renewed. He reprised his role for a brief return from 20 May 2013, before rejoining the regular cast on 5 February 2014. McGregor departed Neighbours for a second time on 15 October 2019, but returned for a guest stint as part of the show's 35th anniversary celebrations on 17 February 2020. Mark is introduced as the lead detective in the attempt on Paul Robinson's (Stefan Dennis) life. He receives conflicting information from the suspects he interviews, and struggles to identify the culprit. McGregor enjoyed being involved in the storyline, as he had never had that much responsibility before. To prepare for the role, McGregor researched his character's job. Mark is portrayed as a charming perfectionist. He is dedicated to his job in the police force and often puts his work ahead of everything else. As a consequence, he struggles to balance his work and personal lives. McGregor found that he shared some similarities with Mark and he enjoyed getting into character. Producers soon established a relationship between Mark and Kate Ramsay (Ashleigh Brewer). The couple faced various obstacles, including Kate's jealous ex-boyfriend, an age gap, and Mark's focus on his work. Mark later has a one-night stand with Jade Mitchell (Gemma Pranita), and reports a fellow officer for corruption, which results in his life being threatened. The character left for witness protection during a special real-time episode. Following McGregor's decision to reprised the role, Mark's later storylines saw him reunite with Kate and deal with her death. Producers then paired him with Paige Smith (Olympia Valance) and three members of his family were introduced. The character has been mostly well received by critics and viewers during his time on the show.