The merger will take effect as of January 2011 and will have a combined work force of over 2,300 employees spread throughout 83 offices in 44 countries worldwide. Public Strategies has 175 employees.
Public Strategies founder and chairman, Jack Martin, will become global executive chairman for H&K, with Paul Taaffe remaining global CEO of the agency.
Former George W. Bush adviser Dan Bartlett will broaden his role to become president and CEO of H&K USA and chairman and CEO of Public Strategies.
Taafe said: 'Combining with Public Strategies gives H&K clients access to even more value as well as adding critical mass in the financial sector and research capabilities.'