Schwarzenberg married Margaretha Freiin Hartard von Pallant in 1613, but his wife died two years later while giving birth to his second son, Johann Adolf.

In the following years, Schwarzenberg became a member of Brandenburg's Privy Council, where he quickly acquired a position of prominence, especially regarding Brandenburg-Prussia's Rhenish territories.

When Sweden became involved in the war, the Calvinist chancellor Sigismund von Götzen gained control and forced Schwarzenberg to retire to Kleve in 1630.

When Frederick William acceded to Brandenburg's throne in 1640, he began curtailing the powers of Schwarzenberg, assuming them himself or granting them to Götzen.

[8] Frederick William had long resented Schwarzenberg, believing that the minister had tried to poison him in 1638 when the prince was ill with measles.

[8] Although his administration of Brandenburg's meager resources was largely unsuccessful during the Thirty Years' War, it marked the beginning of the state's curtailment of the estates, a process continued by Frederick William, the "Great Elector".

Schwarzenberg's successor as Governor of Brandenburg, Samuel von Winterfeld, negotiated a treaty of peace with Sweden.

Before the August 1919 abolition of nobility as a legal class, titles preceded the full name when given (Graf Helmuth James von Moltke).