Lenz was born in Dorpat (Tartu), Livonia, in what is now Estonia. After completing his secondary education in 1820, Lenz studied chemistry and physics at the University of Dorpat. He traveled with Otto von Kotzebue on his third expedition around the world from 1823 to 1826. On the voyage Lenz studied climatic conditions and the physical properties of seawater.
After the voyage, Lenz began working at the University of St. Petersburg, where he later served as Dean of Mathematics and Physics from 1840 to 1863 and Rector from 1863 until his death in 1865. He began studying electromagnetism in 1831. Besides the law named in his honor, Lenz also independently discovered Joule's law in 1842; to honor his efforts on the problem, it is also given the name the "Joule-Lenz law" He died in Rome after suffering a stroke.