Mikhail Vasilyevich Alekseev was born on November 3 (15), 1857, in Vyazma to an officer who participated in the defense of Sevastopol. He received his education at the Tver Classical Gymnasium and then graduated from the Moscow Infantry Cadet School. In 1876, Alekseev became a second lieutenant in the 64th Kazan Infantry Regiment and in July 1877 went to war against Turkey. He was wounded near Plevna and awarded the Orders of Saint Stanislaus and Saint Anna for bravery. Starting his service from the bottom and having no connections, Alekseev did not achieve the rank of company commander in the first nine years.

In 1887, he entered the Nikolaev Academy of the General Staff after 11 years of service, although this usually happened after three years. Alekseev was distinguished by his diligence and graduated from the academy in 1890 with honors. In 1894, he became a colonel and soon a professor of the history of Russian military art at the Nikolaev Academy. From May 1904, he was a major general and head of the department of the General Staff.

During the Russo-Japanese War, starting in October 1904, Alekseev was the chief of staff of the 3rd Manchurian Army and was awarded the Golden Weapon for distinction. With the onset of World War I, he became the chief of staff of the Southwestern Front. In September 1914, after the capture of Lviv, he received the Order of St. George 4th class and was promoted to general of infantry. Alekseev developed the Galician operation of 1914, which was unsuccessfully implemented by Front Commanders Ruzsky and Ivanov.

In March 1915, Alekseev was appointed commander-in-chief of the armies of the Northwestern Front, replacing the ailing Ruzsky. In the summer of 1915, when the German command concentrated forces against Russia, Alekseev successfully extricated the armies from the Polish pocket.

In August 1915, Nicholas II appointed Alekseev chief of staff of the Supreme Commander. By the fall of 1915, the great retreat of the Russian army was completed, and from the spring of 1916, it began an offensive that soon led to the Brusilov Offensive on the Southwestern Front.

Alekseev was a recognized military authority, preferring cautious actions. He remained loyal to the Sovereign despite rumors of his involvement in a Masonic conspiracy. However, his political instincts proved weak. In late February and early March 1917, Alekseev believed false assurances from Petrograd that Nicholas II's abdication would be beneficial for the conduct of the war. He did not prevent the abdication but soon realized the deception and deeply regretted it.

After the abdication of the tsar, the Provisional Government appointed Alekseev as Supreme Commander, but on May 22, 1917, he was removed after criticizing the new authorities. He was replaced by Brusilov.

Alekseev again took the position of chief of staff of the Supreme Commander to save General Kornilov from revolutionary court, but on September 10, he handed it over to General Dukhonin. In October 1917, he went to Petrograd to participate in the Council of the Republic and began to create an underground military organization to fight Bolshevism.

During the October Revolution, Alekseev tried to organize defense but left the headquarters due to a lack of forces. On November 2, 1917, he arrived at Ataman Kaledin in Novocherkassk and called on officers to save the homeland. The Alekseev organization began to form, and on December 6, General Kornilov arrived, who took command of the forces renamed the Volunteer Army.

Alekseev participated in the Ice March, after which Kornilov was killed and replaced by Denikin. After the capture of Ekaterinodar in August 1918, Alekseev focused on establishing civil administration. He approved the creation of the Special Conference, the civil government of the White South.

In the fall of 1918, Alekseev planned to travel to the Urals to lead the Ufa Directory but died on October 8 and was buried in Ekaterinodar. In 1920, his widow transferred his remains to Serbia, where a monument was erected at the New Cemetery in Belgrade.