When he wasn't teaching his students in the United States about 20th-century writers and philosophers, Jarosinski was trying to write a book on transparency as a political metaphor in post-Wall Germany.
He readily admits he was averse to the Internet - it meant having to deal with an avalanche of work emails and he was "never the type" to sit at home reading blogs, the 43-year-old said.
Then two-and-a-half years ago a friend introduced him to Twitter whose point, he said, he didn't understand at first. But through following several comedians and writers, he came to see the potential of the microblogging site.
It sparked what he calls his "little experiment", probing life's complexities in his Twitter feed @NeinQuarterly in a style that is ironic, melancholic, funny or intriguing in up to 140 characters.
"Youth. Wasted on the wrong demographic," reads one.
"A gentle reminder that today was just a symptom. We're the problem," reads another, or: "Every now and then you should step back. Take a look at your life. And keep stepping back."
Written in German and/or English from his smartphone, Jarosinski has struck a chord among users of a form of social media often derided for being overindulgent in tracking the minutiae of everyday life.
His Twitter feed, which he dubs "A Compendium of Utopian Negation", has more than 90,000 followers in an estimated 100 countries and a weekly column in the prestigious German Die Zeit newspaper.
Much of the effect comes from his avatar -- a formidable cartoon image of German philosopher and social critic Theodor W. Adorno wearing a monocle with a stern "Nein" (No) written below his face.
"What I'm interested in is taking the authority that's there in that face, in the words and undercutting it at the same time, but trying to undercut it in a kind of playful and thought-provoking way," Jarosinski told AFP.
"That's always the challenge, that these short things have to do all of that at once. But that's also what I love about it," he said in an interview on the sidelines of this month's Frankfurt Book Fair, where he was promoting a planned book.
Open, witty and with a wide ready smile, he calls what he does "writing jokes" whose form and delivery have evolved over time and are inspired by the aphorisms -- terse or astute sayings or observations -- of writer Karl Kraus, an early 20th-century Austrian writer and satirist, and others.
A gentle reminder that if you've never hated social media, you've probably never loved.— Nein. (@NeinQuarterly) October 17, 2014
Often his pithy philosophical musings play on language, mixing German and English, with puns, inversion, negation or contradiction, and tend to be pegged to current events or daily life.
"Remember, friends: The dative never says die", read a recent one that requires knowledge of German grammar, but Jarosinski, who comes from Wisconsin and lives in New York, said he was mindful to avoid only "inside jokes".
Nor is he seeking to popularise the thinkers and works that have long fascinated him, he added.
"What I'm trying to do is simply say, that to honour the spirit of this work also means to be critical of this work and that you can play with this stuff," he said.
"That it doesn't have to be fetishised."
He's a critical reviewer of his own tweets and typically later deletes about a third but enjoys the instant reaction they can prompt, likening it to "a comedian who tries new material".
"Sometimes someone comes back with a better punchline... that's thrilling," he said.
His success with Twitter's "little box" where users are restricted to composing the briefest of messages has helped draw a line under the angst, isolation and frustration he felt in his academic writing, he said.
"It feels so different than the emptiness of a whole page on a laptop and so those constraints for me really brought about the creativity," said Jarosinski, who cites a high-school love as the spark for having learnt German.
In July, he left the University of Pennsylvania where he was assistant professor of German, and is now working on a new book "Nein. A Manifesto", due to be published in various countries from 2015.
After his previous leap from scholarly writing to Twitter, his switch back to print will feature four-liners whose style emanates from the "spirit" of his tweets but is not a "book of tweets", he said.
He's also currently on the second of what he terms his #FailedIntellectual Goodwill Tour, with universities or other forums in Europe, North and South America inviting him to talk about @NeinQuarterly.
The idea, he said dryly, came from his alter-ego. "My persona has no problem with self-promotion at all."