Lawler joins Momentum after working as a consultant strategic planner and digital strategist for clients such as Fortnum & Mason and William Grants.
He spent the majority of his agency career at Claydon Heeley Jones Mason, which he joined at its inception in 1991, working across a broad range of client business including 3 mobile, COI, Pepsico, British Airways, Diageo and Carlsberg.
Davis joins Momentum from Chemistry Communications Group, where he was creative services director.
He has also worked for AOL Broadband, Universal Pictures International and agencies such as Manifesto Marketing and Scream Creative.
Paul Biggins, chief executive of Momentum London, said: "Tim is an inspirational strategist and a truly creative thinker, with a wealth of experience of incisive planning. Christopher has an exceptional talent in bringing together systems to a multi-disciplined creative process.
"Both will be pivotal in raising the creative standard across all channels, and we are delighted they are joining us."