Alexey Alekseevich Brusilov came from the noble family of Brusilovs. He was born in Tiflis to Major General Alexey Nikolaevich Brusilov and Maria-Louise Antonovna, of Polish descent. In 1867, he entered the Page Corps, graduating in 1872, after which he was assigned to the 15th Dragoon Tver Regiment. In 1873 and 1878, he served as the regiment's adjutant and participated in the Russo-Turkish War in the Caucasus, distinguishing himself during the capture of the fortresses of Ardahan and Kars. For this, he was awarded the Orders of Saint Stanislaus and Saint Anna.

In 1881, Brusilov began his service in Saint Petersburg, completed a course for commanders, and served in the Officer Cavalry School, where he held various positions, including head of the school. He became a well-known specialist in cavalry riding and sports. In 1906, with the support of Grand Duke Nikolai Nikolaevich, he was appointed commander of the 2nd Guards Cavalry Division and later commanded the 14th Army Corps.

With the onset of World War I, on July 19, 1914, Brusilov took command of the 8th Army, which participated in the Battle of Galicia and achieved victories in several battles, including the Rogatin battles and the capture of Halicz. In 1915, despite difficult conditions, his army successfully defended and inflicted defeats on the enemy.

In 1916, Brusilov led the Southwestern Front and conducted a successful offensive known as the Brusilov Offensive. For this, he was nominated for an award but received the Georgievsky weapon with diamonds. During the February Revolution, he supported the Provisional Government and the creation of shock battalions.

After his retirement in 1917, Brusilov lived in Moscow. In 1920, he joined the Red Army and participated in developing recommendations for its strengthening. In 1921, he headed the commission for cavalry training, and from 1923 to 1924, he was the inspector of cavalry of the Red Army.

Alexey Alekseevich Brusilov passed away on March 17, 1926, in Moscow and was buried at the walls of the Smolensk Cathedral of the Novodevichy Monastery.