Velichko Dimitrov Kerin was born on October 19, 1897, in the village of Kamenitsa, which was then part of the Principality of Bulgaria. His parents were Dimitar Kerin and Risa Baltadzieva, who were local peasants. Velichko received his primary education in Kamenitsa. When he was 14 years old, his mother died. After her death, he had to help his father support the family, which included his younger brother and two sisters.

Later, Velichko joined the military service in Plovdiv. He served in the engineer corps during World War I. After the war ended, he worked as both a driver and a watchmaker. In his younger years, he was known to have a problem with alcohol, but he later changed his lifestyle and became a vegetarian. In 1919, he got married, and in 1923, his daughter Latinka was born. His first marriage ended in divorce in 1925, but he remarried shortly afterward.

Velichko lived in Sofia until 1932. He reportedly claimed to have been born in a village called Patrick, near Štip, which was destroyed by the Serbian army during the Second Balkan War. His parents were believed to have become refugees in Bulgaria. Throughout his life, he used various aliases, including Vlado Georgiev Chernozemski and Vlado the Chauffeur. Even his second wife was unaware of his true name and background.

After being released from prison, Vlado Chernozemski disappeared from Bulgaria. He moved to Italy and became an instructor for the Ustaše at a camp in Borgotaro. Later, he was transferred to a camp in Janka-Puszta, Hungary, where he planned the assassination of King Alexander I of Yugoslavia. Chernozemski trained a small group of Ustaše members and went to Paris with them in late September 1934.

On October 9, as the king traveled in a motorcade through Marseille, Chernozemski approached the king's car while holding a bouquet of flowers that concealed his weapon. He yelled "Vive le roi," which means "Long live the King," and then shot King Alexander twice. The king died quickly from his wounds. As chaos erupted at the scene, Chernozemski also unintentionally shot the chauffeur and was involved in the shooting that killed French Foreign Minister Louis Barthou, who was struck by a police bullet.

After the shooting, Chernozemski attempted to escape but was confronted by the police and a cavalryman. He was struck and wounded in the head. An angry crowd then caught him and beat him severely. Despite being taken in for questioning, he could not respond and died from his injuries later that same day.

French police struggled to identify him at first. They only managed to note a distinctive tattoo on his arm. He was buried in an unmarked grave in Marseille with only a few witnesses present. After his death, it was officially confirmed that he was the assassin. His actions were celebrated in Croatian and Macedonian circles, marking him as a significant figure in their history.