Hatfield will take up the new position of head of digital. The role was created to give greater prominence to digital in Rapier's integrated offering.
Hatfield leaves EHS Brann after six years at the agency. During that time, he oversaw the merger of the Euro RSCG Interactive and EHS Brann digital teams to form Euro RSCG 4D Digital.
In addition to the hiring of Hatfield, the agency has strengthened its digital planning credentials with two further appointments.
Neil Johnson joins as a senior planner from eBay, where he was the head of insight.
Darren Burnett has been promoted to the position of head of digital data planning and evaluation. He was previously a senior data planner, and has worked at Rapier for the past five years.
The personnel changes are the first since Alison Meredith was promoted to become the agency's third partner in February. Meredith was handed the new role of head of strategy and development with a brief to raise the prominence of planning and strategy at the agency. The new hirings will report to her.
Meredith said: "Digital is increasingly important for our service brand clients and they've no interest in it living in a separate box.
"John and Neil both have impressive digital credentials and relevant experience, but also a collaborative work style, which is crucial to the way we work at Rapier."
Hatfield said: "I believe the integrated model is the way forward for digital and Rapier is one of the few agencies that has got it right."