Philo Farnsworth married Elma 'Pem' Gardner in Provo, Utah. Pem was a supportive and steadfast partner throughout his life, providing encouragement and stability during the turbulent years of invention and legal battles.

Philo and Pem had four children: Philo Taylor Farnsworth IV, Kenneth Gardner Farnsworth, Russell Gardner Farnsworth, and Kent Gardner Farnsworth. The demands of his work and legal battles often strained his family life.

Farnsworth moved his family to Maine in search of a more peaceful environment and to pursue new research interests outside of television. He established a new laboratory on his farm.

Farnsworth struggled with depression and alcoholism in his later years, exacerbated by the financial and emotional strain of his long career. He faced ongoing financial difficulties due to debt and poor investment decisions.

Philo Farnsworth died of pneumonia in Salt Lake City, Utah, at the age of 64. He was largely unacknowledged for his contributions to television during his lifetime.