Karev completed his early education at the Bulgarian school in Kruševo and in 1893 moved to Sofia, the capital of Principality of Bulgaria, where he worked as a carpenter for the socialist Vasil Glavinov.

[13] In response to an ironic question by Stamatiou, Karev also claimed to be a "direct descendant of Alexander the Great", but added that "history says he was a Greek".

Amongst the various ethno-religious groups (millets) in Kruševo a Republican Council was elected with 60 members – 20 representatives from each one: Macedonian Bulgarians (Exarchists),[19] Vlachs and Slav-speaking, Aromanian-speaking and Albanian-speaking Greek Patriarchists.

After the uprising Karev went back to Bulgaria and became a political activist of the newly founded Marxist Bulgarian Social Democratic Workers' Party (Narrow Socialists).

In 1904, Karev made a legal attempt to return to Macedonia, taking advantage of the Bulgarian-Ottoman Amnesty Agreement for the participants in the Ilinden Uprising.

The applications were received by the Ottoman Amnesty Commission but remained unanswered, despite the intercession of the Bulgarian diplomatic agent in Istanbul, Grigor Nachovich.

Soon after, Karev's detachment was discovered by Ottoman soldiers, and in the ensuing battle he was killed near the village of Rajčani, together with his comrades Dimitar Gyurchev and Krastyo Naumov.

[36] It was removed in 1953 without explanation[37] by the communist leadership led by Lazar Koliševski, as Nikola and his brothers Petar and Georgi were considered to be "Bulgarophiles".

[39] In 2008, a large bronze equestrian monument of Nikola Karev was placed in front of Parliament Building in Skopje, cast by the Ferdinando Marinelli Artistic Foundry of Florence, Italy.