Natascha McElhone left "Designated Survivor" during its second season to pursue a leading role in a new Hulu series titled "The First." This new project, created by Beau Willimon, focuses on the first human mission to Mars and stars McElhone alongside Sean Penn. Due to the commitments required for this new role, McElhone had to exit "Designated Survivor".
Her character, Alex Kirkman, was written out of the show through a dramatic and impactful storyline involving her death in a car accident. This plot development not only addressed her departure but also provided significant narrative momentum for the series.