Mussorgsky died in poverty, but he was born to a wealthy landowning family. Under his mother's tutelage, he developed a facility at the piano, but entered a cadet school in preparation for a military career. He joined a choir and discovered Russian church music, which would profoundly influence his later work.
Upon graduation in 1856, Mussorgsky entered the Russian Imperial Guard. That year he started to socialize with the composers Dargomizhsky and Cui, and through them Balakirev, with whom he began composition lessons. During this period he wrote small piano pieces and songs, and after an emotional crisis in 1858 resigned his commission with the intention of composing full-time. He began to go his own way as a composer in 1861, but was preoccupied helping to manage his family's estate. The decline in his family's fortunes led him to accept low-level civil service positions. He joined a commune with other intellectuals and became a proponent of musical Realism, applying the style to his songs. He had difficulty finishing works in larger formats, but his music circulated widely enough that by the late 1860s he was cast with Balakirev, Cui, Rimsky-Korsakov, and Borodin as part of Russia's "Mighty Handful."
Mussorgsky toiled many years at his masterpiece, Boris Godunov, which reflected in music the inflections of Russian speech and met with great success in 1874. That year he also produced his innovative piano suite Pictures at an Exhibition. Yet his heavy drinking led to his dismissal from government service in 1880. Friends offered some financial help and Mussorgsky occasionally accompanied singers at the piano, but his finances and mental state quickly deteriorated. He died in 1881, leaving it to posterity to sort through and complete his unfinished works of unruly genius.