His father John was a basso, a musician in the Royal Artillery – and his son's first teacher. Sims (birth name: John, as well) made his debut in Newcastle in 1838, as a baritone, in "Guy Mannering" by Henry R. Bishop. After singing small roles at the Drury Lane Theatre in London, he restudied as a tenor in Paris in 1843, sang in Manchester, Dublin and Liverpool. From 1845, he restudied again in Milano. In October 1846, he sang Edgardo (which was to become his greatest role) at La Scala; for the next six months, he toured Italy (including La Fenice) and Vienna, then he returned to London. At the Drury Lane Theatre on December 20th, he was Lyonnel in the world premiere of Balfe's Maid of honour. For the next thirty and more years, Reeves was the most famous British tenor. He sang around the UK: Her Majesty's Theatre, Covent Garden, Drury Lane, Manchester, Edinburgh, Dublin. In 1851, he appeared at the Théâtre Italien in Paris. His roles included Ernani, Florestan, Carlo (Linda di Chamounix), Gennaro, Hüon or Gounod's Faust.