[6] Known for his innocent, dreamy, doe-eyed look, Kilburn achieved fame at the age of 11 portraying Tiny Tim in the 1938 Metro-Goldwyn-Mayer film version of A Christmas Carol, and also as four generations of the Colley family in Goodbye, Mr. Chips (1939).

As a child actor, Kilburn also played leading roles in two films which starred Freddie Bartholomew: Lord Jeff (1938) and Swiss Family Robinson (1940).

In addition to Lord Jeff (1938), Kilburn worked alongside Mickey Rooney in Andy Hardy Gets Spring Fever (1939), A Yank at Eton (1942), and National Velvet (1944).

[7] He made his Broadway debut, credited as Terrance Kilburn, portraying Eugene Marchbanks in a 1952 revival of George Bernard Shaw's Candida.

It presents classic plays, comedies, and musicals, and is known for its annual production of Dickens' A Christmas Carol, adapted by Kilburn's partner, Charles Nolte.