It is the only base the agency has in the UK outside London, though it has had regional offices in the past.
Morris is currently the only person there, but is planning to hire additional staff.
The office is serving local corporate and b2b clients such as cosmetic surgery provider Transform, aviation company Beechcraft and tech firm CommsCare.
Citigate corporate team MD Jonathan Flint said it would give businesses centred in the region "the opportunity to tap into the resources and experience of a big international PR firm yet still get local face-to-face service".
Morris has worked at Citigate, owned by Huntsworth, since 2007. Earlier in his career he worked for a broadcast PR firm and in b2b marketing.
Citigate will be competing with a number of large PR agencies in Manchester including Weber Shandwick, Citypress and Tangerine.