In the live-action film Transformers: The Last Knight, the character known as "Father" refers to Cade Yeager, a central human protagonist. His background is that of a resourceful inventor and robotics expert who was living a quiet life as a struggling single father on a farm in Texas, raising his daughter Tessa after the death of his wife. His inherent creativity and optimistic mind, which he channels into building inventions, are paired with a strong protective instinct, a promise he made to his late wife to keep their daughter safe at all costs.

By the events of The Last Knight, Cades personality has been forged by years of conflict. While he remains a dedicated and fiercely protective father figure, he has also become a hardened fugitive. After the events of Age of Extinction, Transformers were declared illegal on Earth, forcing Cade to go on the run with the Autobot team, including Bumblebee, Hound, and Drift. He is no longer just an inventor but has evolved into an unofficial leader and a skilled field medic for the Autobots, having learned a great deal about Cybertronian biology to treat the wounded. His primary motivation is twofold: to protect the Autobots who have become his family and to survive as a wanted man, having distanced himself from his now college-bound daughter to keep her safe from his dangerous life.

Cades role in the story is that of a pivotal ally to the Autobots and a chosen human hero. He is branded a fugitive by the Transformers Reaction Force, a military organization hunting all Transformers, yet he continues to lead rescue missions to save newly arrived Autobots on Earth. Destiny designates him as a key figure who can broker peace between humans and Transformers, and he is revealed to be the "Last Knight," a human worthy of being a knight of Cybertron. His key relationships include his deep bond with Bumblebee, whom he works with to rescue other Autobots, and his continuing allegiance to the absent Optimus Prime. He also forms a partnership with the British professor Viviane Wembley and the eccentric robot Cogman to find an ancient artifact, Merlin's staff, to prevent the impending collision of Cybertron with Earth.

Cade Yeager undergoes significant development throughout the film. Having been separated from his daughter and living in isolation with the Autobots, he begins the story as a man hardened by years on the run. However, he demonstrates his enduring compassion by taking in a young streetwise orphan named Izabella, becoming a father figure to her as well. His journey culminates in a moment of great heroism when he saves a brainwashed Optimus Prime from the Cybertronian Knights, proving his worthiness as the Last Knight. He also successfully persuades the human TRF to set aside their grudge and fight alongside the Autobots to save the planet, showing his ability to inspire both species toward a common goal.

Notable abilities include his exceptional skills as a mechanic and inventor, which he has adapted to alien technology, making him a proficient field medic capable of repairing severely damaged Transformers. He is also a capable fighter, having learned to wield Cybertronian weaponry and engage in hand-to-hand combat, as evidenced by his previous confrontations with human antagonists. His greatest asset, however, is not a physical ability but his unwavering determination and his unique capacity to see the good in the "junk," a quality that allows him to find treasure and value where others see only scrap, a trait that defines his relationship with the Autobots.