Newly elected cabinet member Eveline Widmer-Schlumpf will take over the justice ministry from her ousted colleague Christoph Blocher in January.
Widmer-Schlumpf, also from the rightwing Swiss People's Party, was widely tipped to take over the department after none of the other cabinet ministers expressed a desire to change portfolio.
Blocher failed in a bid to be re-elected by parliament last week for another four-year term.
Traditionally, when there is a vacancy incumbents can switch ministries based on seniority. New arrivals must take what is left.
Moritz Leuenberger from the centre-left Social Democratic Party remains at the transport, communication and energy ministry; his party colleague Micheline Calmy-Rey will continue as foreign minister; Pascal Couchepin and Hans-Rudolf Merz from the centre-right Radical Party will remain at the interior and finance ministries respectively.
Doris Leuthard from the centre-right Christian Democratic Party will stick with the economy and the other representative of the People's Party, Samuel Schmid, will pursue reforms at the defence ministry.