Originally cast in the lead roles were Sir Rex Harrison and Samantha Eggar, who were replaced by Richard Burton and Lee Remick. When MGM opted to replace Remick with Petula Clark, based on her reviews and Golden Globe nomination for Der goldene Regenbogen (1968), Burton balked at playing opposite a "singer" rather than an "actress", so Peter O'Toole was cast instead.
When the character of Ursula gushes over Mr. Chips, asking Katherine to let her have him when she was done with him, there is some truth in the line. Ursula, played by Siân Phillips, was, in real life, Mrs. O'Toole.
Siân Phillips wrote in her memoir that her husband Peter O'Toole was so well made up as the elderly Mr. Chips, that she walked past him in the canteen without recognizing him.
Peter O'Toole recorded so many takes of Mr. Chips' first solo song, "Where Did My Childhood Go?", that he reportedly told director Herbert Ross: "I think you've got one note from each of the last eighty takes to put the song together!"
In her memoir "Public Places", Siân Phillips wrote that her husband Peter O'Toole refused to rehearse their scenes together.