The agency picked up the £4 million account after a lengthy review process conducted by Beam's new UK management team.
The review follows the joint acquisition of Allied Domecq brands by Beam's parent company, Fortune Brands, and Pernod Ricard.
ZenithOptimedia recently lost its hold on the Allied brands acquired by Pernod Ricard after a consolidation into Vizeum.
However, the Beam win means it will add media planning and buying for the Jim Beam brand and the Maker's Mark brand to its Courvoisier, Teacher's and Laphroaig business.
Planning and buying for Jim Beam was previously with Mediaedge:cia, while Maker's Mark did not previously have a UK media agency.
Beam's creative and direct marketing are also being consolidated into Publicis Groupe in the UK. However, Beam is still looking at its media requirements in overseas markets.
Mark Waugh, the deputy managing director of ZenithOptimedia, said: "To support fantastic household names like Teacher's, as well as launch Beam's existing US power brands like Maker's Mark into the UK makes for a great blend of work."