This article needs additional citations for verification. (May 2019)
|Died||April 6, 1937 (aged 67)|
|Years active||1910 - 1921|
His career was at its peak in the earlier short film era particularly in 1912 when Lonergan wrote the scripts for an astonishing 50 films. His sister Elizabeth Lonergan and brother Philip Lonergan were also a notable screenwriters, and his mother Ellen Mahoney Lonergan was a newspaper society editor.