The pair will now take responsibility for running the agency's creative department with a brief to improve its creative output.
The move also sees Chris Clarke, the global creative director, moving his attention away from the UK office and fully on to LBi's global creative offering.
He said: "We've built our proposition around building believable brands and, to take that forward, we've promoted two key individuals who have a passion for strong creative."
Jordan-Bambach joined LBi as its creative director in January. She was formerly the head of art at glue London. Since then, she has worked on the successful 118 118 pitch.
Gill joined the agency from tmg, where he was also a creative director, in July 2006. He has worked on accounts such as Tourism Ireland, Orange, HMV and Barratt Homes.