Which Swedish chancellor directed Sweden's policy after Gustavus Adolphus died?

The Swedish chancellor who directed Sweden’s policy after Gustavus Adolphus died was Axel Oxenstierna.

Axel Oxenstierna served as Sweden’s Lord High Chancellor from 1612 until his death in 1654. He was Gustavus Adolphus’s closest senior adviser and helped build the administrative and military systems that made Sweden a major European power.

When Gustavus Adolphus was killed at the Battle of Lützen in November 1632, his heir Christina was only a child. Oxenstierna therefore became the leading figure in the regency council and directed Swedish policy. He also became supreme commander of Swedish forces in Germany, ruling much of the Swedish-occupied territory from his headquarters in Mainz.

Oxenstierna helped shape the Instrument of Government of 1634, which clarified Sweden’s central administration and the authority of its great officers. Charles X Gustav became king much later, while Johan Banér and Lennart Torstensson were important generals rather than the chancellor directing national policy.