Larsen is a member of the university's Young Company, a theatre troupe that adapts plays for younger audiences. In 2013, MacKenzie played Henry V in the company's production of Shakespeare's work by the same name.
In 2014, Larsen competed in the Irene Ryan competition hosted at the Region VIII Kennedy Center American College Theatre Festival (KCACTF). The following year, she played the role of Hermione in BYU's production of The Winter's Tale. Also in 2015, she received a national award from the Kennedy Center American College Theatre Festival for Outstanding Performance by an Actress in a Supporting Role for her part in BYU's production of Our Town, directed by Stephanie Breinholt.
- The Daily Herald - Arts hot ticket: Happy Saint Crispin's Day (14 Feb 2013)
- The Daily Herald - Women take center stage in BYU Young Company's 'Henry V' (7 Feb 2013)
- The Universe - The Y Company brings Shakespeare to a younger audience (5 Feb 2013)
- YNews - "Henry V" in theatre for young audiences production at BYU (24 Jan 2013)category 2016 Graduates