Rachet will join the Bournemouth-based team this month, with more than ten years of event design, planning and delivery experience.
At Seventa, Rachet will be helping clients with venue logistics, conference set design, speaker, sponsor and delegate management, and finance and budget management.
He will also work on AV and technical management, and celebrity and music artist bookings.
Rachet said: "I’m looking forward to this new chapter in my career. Having worked on so many previous events, of every shape and size, I will be bringing my expertise to Seventa."
Seventa works with clients including Nationwide Building Society, Liverpool Victoria and The Richmond Group.
Seventa founder Simon Brooks said: "Our business has experienced incredible growth of late and we are thrilled to have someone of Jay’s calibre onboard. His reputation in the local event marketplace is fantastic and his unique array of skills will be to our clients’ benefit on a national scale."