In Star Trek III: The Search for Spock, the Klingon commander pursuing Kirk is Kruge.
Kruge is a Klingon officer played by Christopher Lloyd. He learns that the Genesis Device has created a new planet and believes its technology could become a powerful weapon. He therefore sends his forces to investigate the Genesis Planet, placing him in direct conflict with the crew of the USS Enterprise.
Kruge commands a Klingon battle cruiser and personally oversees the pursuit of Kirk after the Enterprise crew steals the USS Enterprise and travels to the Genesis Planet. His ruthlessness is shown when he orders the destruction of a civilian vessel connected to the Enterprise crew.
Kruge is not the same character as General Chang from Star Trek VI: The Undiscovered Country. Chang is also Klingon, but he appears in a different film and is played by Christopher Plummer, whereas Kruge is played by Christopher Lloyd.