The pitch, which was handled by the AAR, also included incumbent agency Targetbase Claydon Heeley, CMW and Archibald Ingall Stretton.
Geronimo has been briefed to drive customer engagement and unify communications for ING's 'Feels Good' campaign.
Earlier this year, ING moved its ad business from VCCP into Beattie McGuinness Bungay. The Dutch-owned online savings bank is looking to raise its UK profile; Geronimo's first work for it will break next year.