In Battle for the Planet of the Apes (which apparently took place at least 27 years after the events of Conquest of the Planet of the Apes), Bruce MacDonald - brother of Malcolm McDonald who had featured in that movie - was Caesar's human liaison and advisor, and spoke with his authority around Ape City, though he and the other humans otherwise had little authority over themselves, and mostly served the apes. When Caesar wondered after his parents, and what they knew about right and wrong and the future, MacDonald suggested that old video recordings of Cornelius and Zira might have survived, under the wreckage of Modern City (now called the Forbidden City, after it was destroyed in a nuclear war), with answers to some of his questions.
MacDonald and the orangutan Virgil journeyed with Caesar back to the Forbidden City, carrying a Geiger counter and small arms for protection. Discovering the intact (though dilapidated) archives, they scarcely had time to play back a short passage of the "Alien Visitors" (namely, Zira and Cornelius) tape before realising that they had also been discovered – by mutant human survivors of the war. The three barely escaped with their lives, but Caesar now had some insight into who his parents were, and what they knew about future events.
Knowing that there were survivors under the city, who might someday want to wage war against them, Caesar prepared the apes to defend their city, but the head of the ape militia, General Aldo, didn't allow the humans of Ape City to help, or defend themselves. MacDonald and Caesar's hope for integration was caught between Aldo's wish for ape purity, and the mutants dreams of ape annihilation. When the attack came, Aldo actually corralled the humans to keep them from getting involved. The mutants were beaten back, and MacDonald and the other humans were released – but they refused to leave the corral, until their role in the city was redefined.
- Early scripts for Battle for the Planet of the Apes featured MacDonald as the same character from Conquest, but actor Hari Rhodes wasn't available for filming at the time. Instead, the role was given to Austin Stoker - playing his brother - who was apparently a last-minute replacement. Stoker met producer Arthur P. Jacobs & director J. Lee Thompson on 31 December 1972 and was on set on 2 January 1973. "I thought to myself, I've always known acting is a volatile profession, but this is ridiculous... Fortunately we started with physical sequences and didn't get into the dramatics until some time later." A subsequent script revision included (the younger) MacDonald's line: "when the bomb dropped on the city and Caesar heard of my brother's death he said 'my heart is torn.'"
- Marvel Comics' adaptation of Battle for the Planet of the Apes was based on the early scripts of the movie (writer Doug Moench claimed to have not seen the later Apes movies that he adapted to comic format), and consequently featured MacDonald as the same character who appeared in Conquest. Here, he was given the full name 'Bruce ('Mac') MacDonald'. Marvel also published an original story set between Conquest and Battle which detailed how MacDonald and the loyal humans were given their freedom from slavery after the group of slaves led by former Governor Breck rebelled and fled to the destroyed city.
- MacDonald apparently used to supervise the Archives section in the city, according to Kolp in an earlier script revision. The Archives were near the old Command Post where his brother worked with Governor Breck. When Caesar insists "the city was flattened. The bomb left nothing...", MacDonald counters "...except (I suspect) the Archives section - indeed many sections of the underground city were designed to survive the impact of a ten megaton overblast."
- A scene from an early script, which also turned up in Marvel Comics' adaptation, had MacDonald, Abe the Teacher and Sandy the Doctor eat a 'bootleg' rabbit in MacDonald's house, with a chair against the door and blankets on the window to hide the aroma, because Caesar had banned humans from eating meat.
- The script notes for Battle... specify that it is a young black girl who asks a question of The Lawgiver in the epilogue to that film, and that she is possibly descended from MacDonald.
- It is speculated that Malcolm in Dawn of the Planet of the Apes will play a similar role to MacDonald, in the sense that they are both surviving humans who become friends with Caesar and strive for inter-species peace.
- Battle for the Planet of the Apes
- Battle for the Planet of the Apes (novel)
- Battle for the Planet of the Apes (Power Records)
- Planet of the Apes Magazine: Quest for the Planet of the Apes (as the character from 'Conquest' )
- Planet of the Apes Magazine: Battle for the Planet of the Apes (as the character from 'Conquest' )