Rayko Daskalov was born in the village of Byala Cherkva (today a small town), located near Veliko Tarnovo in the central north of the Principality of Bulgaria.

In 1915, Daskalov and other BAPU members were sentenced to jail for their alleged involvement in the Declusiere Affair, a British–French attempt to force Bulgaria into the Entente of World War I.

[3] In prison, Daskalov met Georgi Dimitrov and befriended agrarian leader and future Prime Minister Aleksandar Stamboliyski.

On 27 September, he proclaimed that the monarchist government of Bulgaria was to be overthrown and established the so-called Radomir Republic, with Stamboliyski as its president and himself as commander-in-chief.

Severely wounded in the arm in the skirmishes, Daskalov managed to escape to Thessaloniki, Greece by surrendering to the advancing Entente forces.

[1][2][4] After BAPU won the 1919 elections, Rayko Daskalov was a permanent presence in the party's governments from October 1919 to February 1923, with Stamboliyski as Prime Minister.

In 1922–1923, Daskalov was at the helm of major repressions against IMRO's activity in Pirin Macedonia, the northeastern part of the region allotted by the treaty to Bulgaria.

On 9 June, with Daskalov in Prague, a military-supported coup d'état overthrew Stamboliyski and put in charge a Democratic Alliance government under right-wing politician Aleksandar Tsankov.

The daughter, Svetla Daskalova, would follow in her father's footsteps as a BAPU politician and would become a long-time Minister of Justice (1966–1990)[12] during the communist rule of Bulgaria.

[1] Daskalov was initially interred in Prague's Olšany Cemetery;[10] his burial ceremony was booed by anti-agrarian Bulgarian students in the city.