In January 1919, Brauns was elected to the National Assembly, and in February worked with other delegates to prevent the Betriebsrätegesetz from reflecting radical Räte ideology.
He joined the cabinet of Chancellor Constantin Fehrenbach that same month as Minister of Labour, a position he held for the next eight years under changing heads of government.
This was supposed to be achieved by collective bargaining and work in the Zentralarbeitsgemeinschaft [de], a joint institution of labour unions and employers' association.
This brought him into conflict with the left, since he opposed some of their policies, arguing that getting too close to Social Democratic or Communist positions would remove the reason for existence of the Christian unions and the Zentrum.
After leaving the government, Brauns remained a member of the Reichstag, serving first as vice-chair of the Sozialpolitischer Ausschuss (committee on social policy) and from 1930 to 1933 as its chairman.
In 1931, he chaired a commission named after him, created by chancellor Heinrich Brüning that looked into the causes and ramifications of the Great Depression.
His connections and frequent travels abroad caused him to be very critical of the Nazi takeover of power in 1933 and made him pessimistic about the path the country was taking.