Liam English has spent the past three-and-a-half years as deputy director of comms and head of media relations at HM Treasury and the Cabinet Office.
He joins Lilly, one of the world's largest pharma firms, as an associate director for the Australian, Canada and Europe (ACE) region.
The appointment follows a strategic review of the firm's comms and policy team in its ACE Brussels office.
English will report to Stuart Hurst, senior director, European government affairs and comms advocacy ACE, and Jeffrey Winton, vice-president, global comms.
In the role, which English starts this week, he will be supported by another recent appointment, policy and comms manager Femke Beumer.
In Whitehall, English led pan-departmental campaigns including the publication of spend data and a promotional campaign on best practice procurement.
Before that, he worked in public and community relations for BBC TV Licensing and in the BBC corporate press office.
Hurst said: 'We have just undergone a strategic reorganisation of the Brussels' public affairs and comms office to best place us for the years ahead. The new, dedicated team represents a cadre of expertise that will help shape the organisation's journey across the region.'
The news of the appointment coincides with Eli Lilly's announcement of plans to downsize its plant in County Cork, Ireland.
Between 60 and 70 redundancies are expected.