[7][11] In the 1990s, Hartl attended Harvard University for his undergraduate studies, graduating with a bachelor's degree in physics.

[12] Hartl obtained his PhD in Physics from the California Institute of Technology (Caltech) in 2003, where he researched black hole dynamics.

[13] After finishing his PhD, Hartl served as Caltech's editor on a corrected and expanded version of The Feynman Lectures on Physics at the request of Kip Thorne.

[26][27][28] In partnership with Pearson Education, Hartl authored or co-authored five books published under the brand Learn Enough to Be Dangerous.

[1][6][41][42] Hartl's constant has also seen significant adoption, including support for tau in the official Google calculator[43] and inclusion in programming languages such as Microsoft.NET,[44] Java,[45] and Python.