Her spouse became president in 1873. As first lady, Élisabeth de Mac Mahon established and participated in representation, decorated the Presidential Palace, hosted balls where she mixed the old and new aristocracy, dressed in the latest fashion and became the president in the French Red Cross, where she started a charity project in making baby clothing for the poor. Élisabeth de Mac Mahon is known to have exerted influence upon the affairs of state during the presidency of Mac-Mahon.
Her opinion about various political ministers and officials were respected, and she supported the claims of the count of Chambord on the throne of France.
She played a part in the 16 May 1877 crisis.