Palmer was sent by the Federation to mediate a peace settlement between the Ziminda and the Buice of Chronian III. He waited at Starbase 42 to be picked up by Capt. James T. Kirk and the USS Enterprise-A. There he impatiently waited for them to arrive. When the Enterprise finally arrived an hour late, Palmer berated Kirk for being late, knowing of the crisis on Chronian III. Palmer then showed them the Ziminda's leader, Takula's message to the Federation Council asking for help and mediation. Palmer told Kirk that he hoped the presence of a starship would let the people of Chronian III know that the Federation is supporting their efforts for peace.
Palmer, along with Capts. Kirk, Spock, and Commander Pavel Chekov to meet with Takula and Kime, leader of the Buice. However, Kime refused to listen to Palmer and Kirk, threatening to kill them. When Takula and Kime tried to fight hand to hand with each other, Palmer held them back from each other. He assured them that he would help them establish peace between them, as long as it did not violate the Prime Directive. Following that meeting, Palmer decided to familiarize with Chronian III's culture on his own, despite Capt. Kirk's objections. Palmer was unfortunately, beaten up and was beamed to the Enterprise's sick bay with numerous injuries. (TOS comics: "The Sentence", "Death Before Dishonor")
Following that mission, Palmer went to Starbase 24. There Palmer was questioned by Admiral Galloway about Capt. Kirk's actions on Chronian III. Palmer recommended that, on the record, Kirk gave the Chronians a distorted view of Federation procedure and should be fired. Off the record though, he said thad if had a medal, Palmer would pin it on the S.O.B. himself. (TOS comic: "Repercussions")