As United States Minister to Austria in the service of the Abraham Lincoln administration, Motley helped to prevent European intervention on the side of the Confederates in the American Civil War.

His grandfather, Thomas Motley, a jail-keeper (a public position) and innkeeper in Portland, Maine, had been a Freemason and radical sympathizer with the French Revolution.

Like other successful Boston merchants of the period, Thomas Motley devoted a great part of his wealth to civic purposes and the education of his children.

[4] His education included training in the German language and literature, and he went to Germany to complete these studies at Göttingen, during 1832–1833, during which time he became a lifelong friend of Otto von Bismarck.

Bismarck recalled his early impression of Motley: "He exercised a marked attraction by a conversation sparkling with wit, humor or originality....The most striking feature of his handsome and delicate appearance was his uncommonly large and beautiful eyes.

It was poorly received, but has later been recognized for featuring a valuable portrayal of Bismarck, "thinly disguised as Otto von Rabenmarck", as a young student.

[7] In 1841, Motley entered the U.S. diplomatic service as secretary of legation in St. Petersburg, Russian Empire, but resigned his post within three months, because of the harsh climate, the expenses living there, and his reserved habits.

It was quite popular in its day, but modern scholars argue: Motley's overdramatization and didacticism, combined with research less intense than Prescott's or Parkman's, have cost his works in staying power.

Though he admired Motley's gifts as an author, and stated that he continued to hold the work as a whole in high regard, he stressed it still required "addition and correction".

[1] The humanist historian Johannes van Vloten was very critical, and responded to Fruin in 1860: "I agree less with your too favorable judgement....We cannot build on Motley['s foundation]; for that—apart from the little he copied from Groen's Archives and Gachard's Correspondences—for that his views are generally too obsolete."

[citation needed] At this point the English census of 1861 confirms that he was living with his wife and two daughters at 31 Hertford Street, in the parish of St George's, Hanover Square, London and describing himself as an 'author - history'.

Motley had angered Grant when he completely disregarded Secretary of State Hamilton Fish's carefully drafted orders regarding settlement of the Alabama Claims.

[14] After a short visit to the Netherlands, Motley again went to live in England, where the Life and Death of John Barneveld, Advocate of Holland: with a View of the Primary Causes and Movements of the Thirty Years War appeared in two volumes in 1874.