Created in 2011 by Fog Creek Software,[5] it was spun out to form the basis of a separate company in New York City in 2014[6][7][8] and sold to Atlassian in January 2017.

[11] In September 2011 Wired magazine named the application one of "The 7 Coolest Startups You Haven't Heard of Yet".

[24] In 2020 Craig Jones, then cybersecurity operations director at Sophos, found that the company exposed the personally identifiable information (PII) data of its users, exposed through public Trello boards; the researcher first tweeted about this issue in the year 2018.

[31] According to a Fog Creek blog post in January 2012, the client was a thin web layer which downloads the main app, written in CoffeeScript and compiled to minified JavaScript, using Backbone.js,[32] HTML5 .pushState(), and the Mustache templating language.

[33] On January 26, 2017, PC Magazine gave Trello a 3.5 / 5 rating, calling it "flexible" and saying that "you can get rather creative", while noting that "it may require some experimentation to figure out how to best use it for your team and the workload you manage.