The Secret Agent is said to have influenced the Unabomber—Theodore Kaczynski. Kaczynski was a great fan of the novel and as an adolescent kept a copy at his bedside. He identified strongly with the character of "the Professor" and advised his family to read The Secret Agent to understand the character with whom he felt such an affinity. David Foster, the literary attributionist who assisted the FBI, said that Kaczynski "seem[ed] to have felt that his family could not understand him without reading Conrad."
Kaczynski's idolisation of the character was due to the traits that they shared: disaffection, hostility toward the world, and being an aspiring anarchist. However, it did not stop at mere idolisation. Kaczynski used "The Professor" as a source of inspiration, and "fabricated sixteen exploding packages that detonated in various locations". After his capture, Kaczynski revealed to FBI agents that he had read the novel a dozen times, and had sometimes used "Conrad" as an alias. It was discovered that Kaczynski had used various formulations of Conrad's name – Conrad, Konrad, and Korzeniowski, Conrad's original surname – to sign himself into several hotels in Sacramento. As in his youth, Kaczynski retained a copy of The Secret Agent, and kept it with him whilst living as a recluse in a hut in Montana.