Sergei Alexandrovich Koussevitzky was born on July 26, 1874 in Vyshny Volochyok.  His father, a retired military musician and independent  craftsman, passed on his love of music to his four sons.

From the age of six, Sergei studied viola, then cello and double bass. At the age of fourteen, Sergei secretly left home and travelled to Moscow to enrol at the Conservatoire. He was flatly rejected - admission for that year was already over. Then he goes to the Music and Drama School of the Moscow Philharmonic Society, where he persuades the director to listen to his playing. Convinced of the young man's perfect ear and excellent musical memory, the director recommended the double bass class and helped him to get a scholarship.

Koussevitzky was tall, strong (and mastering the double bass requires great physical effort) and talented. So two years later he was already accepted into Savva Morozov private opera in Moscow. The abilities of young musician did not go unnoticed: from 1894 he played in the orchestra of the Bolshoi Theatre; then he became concertmaster of the theatre's double bass group, and in 1902, he received the title of soloist with the Imperial Theatres.

As a leading double bass virtuoso, Koussevitzky began to perform in European countries on tour. The musician was invited to play in Great Britain, the Czech Republic and Germany. The best musicians of the time, including Fyodor Chaliapin, Leonid Sobinov and Sergei Rachmaninoff, invited him to take part in their concerts. Since few works have been written for the double bass, Koussevitzky himself makes arrangements of pieces and concertos by George Frideric Handel, Wolfgang Amadeus Mozart and Camille Saint-Saëns for this instrument.

The first marriage of Koussevitzky with the Bolshoi Theatre actress Nadezhda Galat broke up, and Sergei married Natalia Ushkova, a student pianist at the Philharmonic School, daughter of Moscow millionaire Konstantin Ushkov, a prominent patron of arts and honorary director of the Moscow Philharmonic Society, one of the first shareholders of the Moscow Art Theatre. This gives the young man financial independence, meaning he can leave the orchestra.

In 1905, Sergei Koussevitzky and his wife moved to Germany, where a new stage in the musician's life began. He devoted more time to the art of conducting, attending concerts by renowned maestros, and his mentor was Arthur Nikisch – one of the greatest conductors of the late 19^th and early 20^th centuries and a prominent example of the Romantic movement in the performing arts. Within three years Koussevitzky had mastered a new activity and made his debut with the Berlin Philharmonic Orchestra. As his first work, he performed the Second Piano Concerto by Sergei Rachmaninoff.

A significant part of the Ushkovs' large fortune – with his father-in-law consent – was channelled to musical and educational purposes in Russia.  In 1909, Koussevitzky organised a new "Russian Music Publishing House", which popularised the work of young Russian composers. This publishing house published many works by Alexander Scriabin, Igor Stravinsky, Nikolai Medtner, Sergei Prokofiev and Sergei Rachmaninoff. Moreover, Koussevitzky assembled his own orchestra of 75 musicians and spent concert seasons in Moscow and St Petersburg performing what he considered to be the best works of world music, including new Russian music.

After the October Revolution, the musician was deprived of almost everything – his publishing house, symphony orchestra, art collections and a fortune of millions were nationalised. Captivated by the enticing slogans "art for the masses", consonant with his ideals of enlightenment, Koussevitzky participated in numerous "people's concerts" for proletarian audiences, students, military personnel, and in the work of the artistic council under the concert subdivision of the music department of the People's Commissariat of Education.

Sergei Koussevitzky left the country in 1920. In 1921, in Paris he re-established an orchestra and the Koussevitzky Symphony Concerts society, and continued his publishing activities. He took part in the production of “Khovanshchina” at the Grand Opera House and staged Boris Godunov and “Khovanshchina” together with the famous stage director Alexander Sanin at the Gran Teatro del Liceo in Barcelona.

In 1924, Koussevitzky was invited to become Principal Conductor of the Boston Symphony Orchestra. Soon this symphony orchestra became the leading ensemble first in America and then in the entire musical world. The conductor left such a mark on the orchestra's history that it is now commonly divided into BK (before Koussevitzky) and AK (after Koussevitzky). The musician founds the Berkshire Music Centre, which becomes a kind of musical Mecca of America, since 1938, constantly organises a summer festival in Tanglewood (Massachusetts), which attracts up to a hundred thousand people.

Sergei Alexandrovich did not lose his ties with Russia: during World War II, the musician became chairman of The American Committee for Russian War Relief and raised funds for the Red Army, served as president of the music section of the National Council of American-Soviet Friendship, and in 1946 became chairman of the American-Soviet Musical Society.

Celebrating Koussevitzky's merits to music and society in France in 1920-1924, the French government awarded him the Legion of Honour (1925). In the United States, many universities conferred on him the honorary title of professor. Harvard University in 1929, and Princeton University in 1947, conferred on him the honorary degree of Doctor of Arts.

Sergei Alexandrovich died on June 4, 1951 in Boston, and is buried there.