New Commander: Gen. Clark Succeeds Ridgway As UN Chief. General Mark Clark takes over command of United Nations forces in Korea, as General Matthew Ridgway (for search purposes: Matthew Ridgeway) leaves to take over NATO forces in Europe, succeeding General Eisenhower. General Ridgway says farewell to unit chiefs and General Clark greets his new command. General Van Fleet is in some of these pictures, too. A crowd of photographers (they look to be military personnel) take aim with their cameras.