Dostoevsky was Russian on his mother's side. His paternal ancestors were from a place called Dostoyeve, natives of the government of Minsk, not far from Pinsk. The last name of the paternal family is assumed to be 'Rdishev' prior to its assumption of the township eponym 'Dostoevsky', though the ethnic origins of his paternal ancestors remain in dispute. According to one theory, Dostoevsky's paternal ancestors were Polonized nobles (szlachta) and went to war bearing Polish Radwan Coat of Arms. Dostoevsky (Polish "Dostojewski") Radwan armorial bearings were drawn for the Dostoevsky Museum in Moscow. The family eventually passed into Ukraine. (Dostoyevsky 2001, pp. 1, 6-7)

Dostoevsky was the second of seven children born to Mikhail and Maria Dostoevsky. Dostoevsky's father Mikhail was a retired military surgeon and a violent alcoholic, who served as a doctor at the Mariinsky Hospital for the Poor in Moscow. The hospital was situated in one of the worst areas in Moscow. Local landmarks included a cemetery for criminals, a lunatic asylum, and an orphanage for abandoned infants. This urban landscape made a lasting impression on the young Dostoevsky, whose interest in and compassion for the poor, oppressed, and tormented was apparent. Though his parents forbade it, Dostoevsky liked to wander out to the hospital garden, where the suffering patients sat to catch a glimpse of sun. The young Dostoevsky loved to spend time with these patients and hear their stories.

There are many stories of Dostoevsky's father's despotic treatment of his children. After returning home from work, he would take a nap while his children, ordered to keep absolutely silent, stood by their slumbering father in shifts and swatted at any flies that came near his head. However, it is the opinion of Joseph Frank, a biographer of Dostoevsky, that the father figure in The Brothers Karamazov is not based on Dostoevsky's own father. Letters and personal accounts demonstrate that they had a fairly loving relationship.

Shortly after his mother died of tuberculosis in 1837, Dostoevsky and his brother were sent to the Military Engineering Academy at Saint Petersburg. Fyodor's father died in 1839. Though it has never been proven, it is believed by some that he was murdered by his own serfs.[3] According to one account, they became enraged during one of his drunken fits of violence, restrained him, and poured vodka into his mouth until he drowned. Another story holds that Mikhail died of natural causes, and a neighboring landowner invented the story of his murder so that he might buy the estate inexpensively. Some have argued that his father's personality had influenced the character of Fyodor Pavlovich Karamazov, the "wicked and sentimental buffoon", father of the main characters in his 1880 novel The Brothers Karamazov, but such claims fail to withstand the scrutiny of many critics.

Dostoevsky had epilepsy and his first seizure occurred when he was 9 years old.[4] Epileptic seizures recurred sporadically throughout his life, and Dostoevsky's experiences are thought to have formed the basis for his description of Prince Myshkin's epilepsy in his novel The Idiot and that of Smerdyakov in The Brothers Karamazov, among others.

At the Saint Petersburg Academy of Military Engineering, Dostoevsky was taught mathematics, a subject he despised. However, he also studied literature by Shakespeare, Pascal, Victor Hugo and E.T.A. Hoffmann. Though he focused on areas different from mathematics, he did well on the exams and received a commission in 1841. That year, he is known to have written two romantic plays, influenced by the German Romantic poet/playwright Friedrich Schiller: Mary Stuart and Boris Godunov. The plays have not been preserved. Dostoevsky described himself as a "dreamer" when he was a young man, and at that time revered Schiller. However, in the years during which he yielded his great masterpieces, his opinions changed and he sometimes poked fun at Schiller.