He was sole Minister to the President of the Confederation (after 1870 to the Emperor).

The President (who was King of Prussia) could declare peace and war, sign treaties, and appointed all officials, but all his acts required the signature of the Chancellor, who was thereby Foreign Minister of the Confederation and had the whole of the patronage.

More than this, he was at the head of the whole internal administration; from time to time different departments of State were created,--marine, post-office, finance,--but the men who stood at the head of each department were not co-ordinate with the Chancellor; they were not his colleagues, but were subordinates to whom he delegated the work.

They were not immediately responsible to the Emperor, Council, or Reichstag, but to him; he, whenever he wished, could undertake the immediate control of each department, he could defend its actions, and was technically responsible to the Council for any failure.

Of course, as a matter of fact, the different departments generally were left to work alone, but if at any time it seemed desirable, the Chancellor could always interfere and issue orders which must be obeyed; if the head of the department did not agree, then he had nothing to do but resign, and the Chancellor would appoint his successor.
The Chancellor was, then, the working head of the Government; but it will be said that his power would be so limited by the interference of the Emperor, the Council, the Parliament, that he would have no freedom.
The contrary is the truth.