Han was born in Aurora in the year 4486 AD, the son of Vasilia Fastolfe. He early showed great ability in the field of rootics, making his mark in the science before reaching the age of a hundred. Fascinated with the positronic brain, but also the human brain, he dreamed of perfecting Laws of Humanics, which he called “psychohistory”. His first daughter was named Lumen. His second, with another woman, was named Vasilia after his mother. Vasilia's mother had wanted a son, but Han would not give his consent to artifical insemination with selected sperm, insisting on "the natural throw on the genetic dice". Unusually, Fastolfe decided to bring Vasilia up himself. Eventually, Vasilia offered to make love with Fastolfe but he refused, significantly weakening their relationship. Despite Han's attempts to reconcile it, Vasilia ultimately moved to another establishment, severed contact with him and renamed herself Vasilia Aliena.
By the year 4720, he had also become an influencial politician on Aurora and a vocal member of the Auroran Humanist Party, in contrast to both his daughters, who had joined the Globalist Party headed by Fastolfe's main political opponent Kelden Amadiro. In this year, he established himself as one of the great roboticists of history when he created the first "humaniform" robot, R. Daneel Olivaw, with Dr Roj Nemennuh Sarton. When Sarton was killed, he first met the detective Elijah Baley, who was investigating Sarton's death. During Elijah's investigation, Fastolfe drugged him to install in him the idea of the freedom of Earth and a new wave of settlers. He later recommended Elijah for a small case on the planet Solaria, which also resulted in Fastolfe taking in Gladia Delmarre from the planet.
In 4724, he created another humaniform robot, R. Jander Panell, who he gave to Gladia, but Jander was mysteriously shut down shortly after, an act which Fastolfe's political enemies led by Kelden Amadiro, who wanted the design for humaniform robots, attributed to him. He called on Detective Baley, with a push from his telepathic robot R. Giskard Reventlov, to prove he did not destroy Jander. During this time, he also spoke to Elijah about his “psychohistory”. This investigation, which ended in Elijiah proving Amadiro's guilt in tampering with Jander, allowed Fastolfe, who had always wanted a second wave of exploration from Earth, to strike a deal with Amadiro and the Globalist Party to allow this, resulting in a new wave of colonisation from Earth which produced the Settlers.
Fastolfe died in the year 4920, acknowledging Gladia on his deathbed as his daughter, not Vasilia, his biological daughter, which she accepted. He also gifted R. Daneel and R. Giskard to Gladia. In terms of his wider legacy, Fastolfe was remembered as a great roboticist and the first psychohistorian.