Marc Reynolds arrived in the village in June 1999 along with his family: his father Sean, his mother Angie and his younger sister Ollie. Marc and Ollie began attending school in Hotten and befriended fellow students Andy and Robert Sugden and Donna Windsor.
Marc begins dating Donna and loses his virginity to her. Marc and Donna continued sleeping together until they were caught in bed together by Donna's mother Viv. Viv later told Angie and Marc's relationship with Donna subsequently ended. Marc then began a relationship with newcomer Eve Birch.
Marc, Ollie, Eve, Donna, Andy, Robert and Katie Addyman went on a night out in Hotten, where they went to a nightclub. After missing the last bus back to Emmerdale, Andy stole a car and Marc agreed to drive the group home. However while driving back to the village they ran over their headmistress Jean Strickland, who was killed instantly. The group managed to destroy the evidence and hide their guilt, but after months of sneaking around Marc confessed and was sent to prison for a year for causing death by dangerous driving, while the rest of the group were sentenced to committing community service.
Upon his release from prison Marc disapproved of his mother's relationship with Cain Dingle. When Angie later died in a car accident Marc left the village to live with his father. Marc reappeared in the village briefly in May 2007 along with his stepmother Tara Thornfield for the funeral of his grandfather Len.