He is the first to be charged as part of the US Justice Department's year-long criminal probe into the firm's rigging of federal air-pollution tests.
James Liang pleaded guilty to violation of the clean air act, a wire fraud count and a consumer fraud count.
Volkswagen has already agreed to spend up to $16bn (£12bn) to address environmental, state and owner claims.
Mr Liang, who is a German national, worked in VW's diesel development department in Germany from 1983 to May 2008, before moving to the US.