Tooher, who has edited the MoS's Financial Mail section for two years, is to join KPMG in the new post of senior media relations manager in the autumn. He will report to UK head of corporate communications Gavin Houlgate.
Houlgate said Tooher would look at KPMG's communications efficiency and would work on two projects about which he declined to give further information.
KPMG is co-operating with a US Justice Department investigation into services it provided between 1996 and 2002. The investigation is part of a wider inquiry into the role of accountancy firms, law companies and large banks in promoting tax havens.