Alexander Pierce

Played by Robert Redford

Alexander Pierce was a senior S.H.I.E.L.D. official who sat on the World Security Council while secretly serving as a high-ranking member of Hydra, which had spent decades embedded within S.H.I.E.L.D. since the end of World War II. He orchestrated Project Insight, a plan to use a fleet of helicarriers to eliminate millions of perceived future threats to Hydra's order, before being exposed and killed.

First turns up in Captain America: The Winter Soldier.