Before the First Robotech War
Before the SDF-3 departed from Earth, he was put in charge of the defense of Earth and rebuilding the Robotech Defense Force. Leonard was not optimistic of the mission, feeling that the REF's exit from Earth Defense would leave the Earth vulnerable to an attack from any alien forces which chose to invade the planet; Zentraedi or otherwise. He predicted that if the mission went through and the Spacefortress did not return home, war against another alien threat would be inevitable. (Robotech II: The Sentinels) It was a fear which would be proven correct within seven years.
The Second Robotech War
He was the leader of the Southern Cross Army that protected the Earth after the SDF-3 parted to Tirol, he was disliked for his "win-or-die" mentality that led to the deaths of many of the Southern Cross soldiers and pilots. During the conflict against the Robotech Masters, he was convinced that the Robotech Masters had to be exterminated in order to win the war.
This led to various internal problems and debates in the Southern Cross' high command where many generals knew that the only way to end the war was through peaceful means.
He was in Monument City during the Robotech Masters' final assault on the Southern Cross, where he said that he would stay to the end. Later a Bioroid shot directly at his office, killing him instantly.