Born in a town in Huelva called Higuera de la Sierra (formerly Higuera next to Aracena or Higuera de Aracena) in 1678, he was the son of Ana Domínguez and Alonso Miguel, members of Spanish nobility, but without fortune. In 1723, he moved to Madrid after having received commissions for imitating royal portraits. The skill he displayed in this work earned him the nickname of ‘Mr Alonso, the Imitator’. In collaboration with Jean Ranc, he achieved renown in the court due to the numerous portraits he painted of figures belonging to Queen Isabella Farnese's inner circle. He accompanied the court to Seville and he may have developed the Queen's interest in and taste for Murillo's paintings. This stay in Seville enhanced Tobar as one of the city's most renowned portraitists. He was appointed court painter in 1733, after Teodoro de Ardemans position became vacant, where he followed the court to La Granja de San Ildefonso. The Prado holds an imitation of Tobar's portrait of Bartolomé Esteban Murillo, based on the painting that Murillo produced for his children, the original of which is located in the National Gallery in London. This was not the only occasion on which Tobar imitated works by Murillo. He occasionally used them as a basis for his own variations on the chosen themes (Sánchez del Peral, J. R. in: Encyclopedia M.N.P., 2006, Volume VI, pp. 2086-2087).