Was 'nervous Nellie' a Real Person?

Nervous Nellie ("a person or animal that tends to be timid or anxious”) sounds like it has been around forever; it’s the sort of phrase your grandmother’s great-great-grandmother might’ve used. But this term has been in common use for just over a hundred years, and we owe most of its popularity to a United States senator. And no, his name was not Nellie.

There is no evidence that nervous Nellie refers to any actual person named Nellie. It seems likelier that the words were combined because people like alliteration, especially when using it to come up with nicknames for types of people (Debbie Downer, Nattering Nabobs of Negativism). The use of nervous Nellie goes back to the second decade of the twentieth century, although it was rare, and usually used of a specific person or thing.

Scene 4, interior of movie theater. Film of ‘Nervous Nellie’ being shown.
— Evening Star (Washington, D.C.), 20 June 1915 Nervous Nellie sees a mad dog on every corner. They’d got her going.
— The Journal (Meriden, CT), 20 Nov. 1917

In the 1920s, Frank B. Kellogg (who served as a U.S. senator from Minnesota and later as secretary of state under President Calvin Coolidge) was saddled with nervous Nellie as his personal nickname. He was known for having a degree of caution that his colleagues often found maddening, for visible nervous tics, and for a tendency to agonize over decisions that others felt should be made more briskly.

Every Senator has a nickname, after he has been in Washington any length of time, and that by which Senator Kellogg was known in the privacy of the Capitol corridors and in all the official by baths derived from real or fancies traits in Senatorial character was “Nervous Nellie.”
— The Baltimore Sun, 27 Oct. 1923

Kellogg, the Gopher, must go back and hunt
For he went too far with his trust-busting stunt
”Nervous Nellie,” they called him, just for the fun
In the Senate, which he leaves, though not on the run
— The Times-Picayune (New Orleans, LA), 5 Mar. 1923

Once it was attached to Kellogg the word increased dramatically in popularity. Before long, the nervous Nellie had escaped its specific context (Frank Kellogg's diplomatic career) and taken on a life of its own. A nervous Nellie became simply anyone who worried too much, fussed over details, or hesitated when boldness was called for. Whether Kellogg himself was aware that his nickname had gone on to such an independent and successful career in the language is, unfortunately, not recorded.