In 1987, Simeonovski graduated from the National High School of Applied Art "St.Luka" in Sofia. From 1989 to 1995 he studied vertebrate zoology at the Sofia University, where he earned his Master of Science degree with a thesis on the aspects of wildcats and feral cats. Simeonovski's scientific interests concentrated on the reconstruction of the external characteristics of fossil mammals, including fur hair, fur coloring and fur patterns, crests, mane and dewlaps. He is also studying anatomy, development, heredity, evolution, adaptive characteristics, and the variation of mammals. Further he uses prehistoric and ancient art as sources of zoological information. In 2010, Simeonovski was a member of the artistic designer team of the exhibition Mammoths and mastodons: titans of the Ice Age in the FieldMuseum of Natural History in Chicago, where he created an artistic rendering of Lyuba, the currently most completely preserved woolly mammoth calf. In 2011, he illustrated the workLes petits mammifères de Madagascar: guide de leur distribution, biology et identification by Voahangy Soarimalala and Steven M. Goodman. In 2014, he illustrated the book Extinct Madagascar: Picturing the Island’s Past by William L. Jungers and Steven M. Goodman about the fossil and subfossil mammal and bird fauna of Madagascar which was also a subject for an exhibition in the Field Museum of Natural History in Chicago that run from August 2014 to October 2015. In 2016, Simeonovski illustrated the book Horned Armadillos and rafting Monkeys: The Fascinating Fossil Mammals of South America by Darin A. Croft on the fossil mammal fauna of the Cenozoic in South America. That same year he was part of the illustrator team of the book The Mammals of Luzon Island. Biogeography and Natural History of a Philippine fauna by Lawrence R. Heaney, Danilo S. Balete and Eric A. Rickart. , illustrated by Velizar Simeonovski for the journal PLoS ONE in 2011. Simeonovski also provide illustrations and artistic reconstructions for species description's, including 2011 for Panthera zdanskyi, that same year for the Tsingy wood rail, in 2014 for Yoshi garevskii, and in 2016 for Calciavis grandei. In 2011, Lawrence R. Heaney and his team described seven new species of the mice genus Apomys'' from Luzon and Mindoro in the Philippines where Simeonovski made the illustrations.