Hussain, who joined Promote as managing partner earlier this year, will be responsible for the day-to-day management of the agency.
Her promotion follows a series of new business wins for the agency in recent months, including the London FA and Action for Charity's Ride the Night and Walk the Night events.
Hussain said: "As physical activity and wellness continue to be a priority for the nation, Promote is the agency best placed to support organisations and brands striving to get more people, more active, more often."
Prior to joining Promote in March, Hussain worked on a freelance basis. Before this she was managing partner at Speed Communications. She joined Speed from Bray Leino, where she served as head of its consumer and lifestyle division. Earlier in her career, Hussain was director for consumer brand at Grayling between 2010 and 2011.
Promote, which was established in 1994, specialises in sport, fitness and wellbeing PR.