When restoring the film in 1998 for its 30th anniversary, it was found that the original master 35mm elements for the film were lost. As such, 16mm B-roll footage had to be used instead. Although the sound quality was improved, a majority of the sound effects were lost and a crucial piece of narration by Greer Garson was mistakenly replaced by a scratch track of Paul Frees voicing the line.
The singer of "Why Can't The Animals Smile?" was not Ted Eccles, who provided the speaking voice for Aaron the Drummer Boy, but rather an uncredited Dick Beals, who famously voiced the Speedy Alka-Seltzer mascot, Gumby, and Davey from Davey and Goliath (1960).
The Little Drummer Boy (1968) is Rankin/Bass Productions' third Christmas-themed animated TV special, following Rudolph the Red-Nosed Reindeer (1964) and Cricket on the Hearth (1967). It is also the company's fourth holiday-themed animated TV special following the aforementioned films and Mouse on the Mayflower (1968), and its sixth overall animated TV special.
During the original airing, narrator Greer Garson wished the viewers a Merry Christmas on behalf of The Little Drummer Boy cast and the American Gas Association (the original sponsor). This was repeated a second time over a photo displaying Greer Garson just before the ending Rankin Bass logo.
Though the show was produced by an American studio (Rankin/Bass) and sponsored by American corporations, it was first broadcast in Canada nationwide four days before its U.S. debut.