They were all reporters.
Twain began his journalism career with his real name, Samuel Clemens, but on February 2, 1863, he first signed his work as Mark Twain.
“….Twain the author would not have existed without Twain the journalist….
….Twain, born Samuel Langhorne Clemens in 1835, began his career as a newspaperman at the precocious age of 12, working as a printer’s apprentice for the Missouri Courier after his father died of pneumonia.
From there, he joined his brother Orion Clemens’ paper the Western Union as a typesetter and editorial assistant. He carried his burgeoning career to a number of cities, including St. Louis, Philadelphia, New York and Cincinnati.
During the ensuing years, he famously worked as a riverboat pilot and began using his pen name, Mark Twain, in 1863.”
— “Mark Twain, as a reporter, found recognition after story about Stamford brothers at sea”
Ctpost.com, April 20, 2010
“In April of 1862 he (Samuel Clemens) began sending humorous letters to the Virginia City Territorial Enterprise newspaper. Several of these were over the pen name ‘Josh.’
Clemens moved to Virginia City to join the Enterprise staff in September of the same year. Towards the end of the year he was in the capitol of Carson City observing the meetings of the territorial legislature.
On February 2, 1863, he mailed an article to the Enterprise over the pen name ‘Mark Twain.’ This appeared in print in the March 3, 1863, issue, and soon was on its way to being one of the most recognizable nom de plumes in history.”
— “Samuel Clemens Began Using ‘Mark Twain’ 150 Years Ago“
Mark Twain Boyhood Home & Museum, 2013
Mark Twain, as portrayed by Hal Holbrook, talks about working as a newspaper correspondent in Washington, DC.
“Editor-in-chief Goodman’s instructions to his novice local reporter (Twain), as recalled in Roughing It, were ‘to go all over town and ask all sorts of people all sorts of questions, make notes of the information gained, and write them out for publication.’
In following these guidelines Sam Clemens may not have been the most diligent local reporter — and later local editor — who ever prowled the roistering streets of Virginia City, but he probably was the most imaginative.
Stirring news, he felt, that was what a paper needed, and if he couldn’t find it — well, he could always manufacture it. And so, when the supply of actual events — mining discoveries, accidents, knifings, shootings, fires — was low he enlivened the paper with the products of his fertile mind….”
— “Mark Twain and The Territorial Enterprise“
Territorial Enterprise Foundation, 1999
In 1909, about a year before he died, the old newspaper reporter appeared in his first, and probably only movie. He looks like he would rather be writing.