After initially studying at a seminary in Riga, he went to St. Petersburg after a few years to study law. As his family didn't support this decision, he had to earn his own living, and he did so as a railway clerk.
Drafted into the Russian army in WWI, he was badly wounded in autumn 1915, and demobilized after a long hospital stay. He went back to the St. Petersburg university, but chose history and philology, this time, but he didn't finish those studies either. In 1918, he finally found his vocation, and studied voice at the conservatory, with Ivan Ershov, among others; he graduated in 1923.
Already during his last year at the conservatory, he sang at the Narodnyj dom. After receiving his diploma, he got a contract in Ekaterinburg, but in April 1924, he decided to go home to Riga, meanwhile the capital of the independent Latvian Republic. He made his debut at the Riga opera theater as Grigorij, and he was to stay at that house until 1941. His most important roles were German, Cavaradossi, Prince, Manrico, Radames, Lohengrin, Canio, Stolzing and José.
He also sang abroad a few times, almost always with Shaljapin, who had a liking for him. They first had sung together already in Vasiljevs' first year, at the Narodnyj dom, and Shaljapin had him hired to Berlin in June 1928 for Don Quichotte, where he sang Rodrigo, and for Boris Godunov, where he sang the Simpleton, this time. In December 1929 and January 1930, he was in Barcelona for a Russian season at the Liceu, again with Shaljapin; Vasiljevs was again Rodrigo, and Andrej Khovanskij. He also sang with Shaljapin when the latter visited Riga, in Boris Godunov and in Rusalka.
On record, however, he sang exclusively trifles, mostly pop songs, some operetta... and in a style and voice that make it pretty difficult to imagine him as Grigorij, German, Stolzing or Manrico!
In 1934, he played the main character in the first Latvian musical film, "Tautas dēls" (The son of the people). From 1936, Vasiljevs worked also as a stage director. From 1941 to 1944, under the German occupation, he left Riga for Liepāja, where he doubled once more as a tenor and a stage director.
In 1944, he returned to the Riga opera house, now only as a stage director – a very busy one: he produced another 30 stagings in the following years. From 1945 to 1961, he also taught at the Riga conservatory.