He joins the firm next month in a role created as part of a staff expansion, and will report to managing director Jason Lark.
Gregory leaves Vertis after 10 years with the firm, where his roles included data management responsibility. He was previously systems manager at Tower Publishing Services.
Lark said: "Darron is joining as part of our next stage in expansion where we will reinforce our key message that we can give added value to clients."
Other recent staff hires include the recruitment of former Acxiom acount manager Gillian McKenzie as a senior member of its account management team.
Celerity clients include Nectar, Boots and BBC Worldwide.
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