[2] Calleja is a resident singer, for the 5th year in a row on the now defunct program 'Hadd Ghalik', which is aired on the national Maltese television channel TVM.

His singing career started at the age of 11, he studied voice and in March 2016 he placed 1st in the Trinity College of London vocal exam.

[citation needed] He played many main roles in various musicals and/or pageants over the years, on the local stage, including: 'Aida', 'Rumpilstilskin', 'Barnuza Blu', 'Katrin tal-Imdina', 'The Pantomime Sossy u Tezor Mitluf', 'Carmen', 'Dracula' and 'Star Child'.

All this led him into having a leading role at the Good Friday 2017 and again in 2018 with a different story line Pageant, organised by the inmates at Corradino Correctional Facility in Kordin, Malta, which had all the shows, both years, performed over 2 weeks being sold out.

Calleja decided to take part in the Casting (performing arts) for San Marino's selection for their representative for the Eurovision Song Contest 2018 in Lisbon, Portugal.

2017: Calleja took part in the Ghanja tal-Poplu 2017, he submitted 2 original songs on his own, and one duet, and from over 130 songs submitted he made it through with the duet 'Mill-Ghatba L'Barra'[13] which he performed together with Michela Dalli, live on 2 September 2017 in the Royal Opera House, Valletta (Pjazza Teatru Rjal) which was aired live on TVM.

2017: Calleja after winning the event the previous year (see below 2016) he was invited to perform again as a guest and to pass the trophy to the 2017 winner.

Calleja performed again his winning song from the previous year 'Golden Boy' and he officially released his new single and music video 'Escape'.

For the joy of the fans present during the event he performed a duet with his mentor Glen Vella with their cover of the song 'Fly on the Wings of Love'.

[19] Calleja was also chosen from the Maltese selections to represent Malta in the Microfono D'Oro 2014, held in Mirandola, Italy, with the cover version of Paolo Meneguzzi's song 'Era Stupendo', where he was placed 2nd from 25 competing artists from different countries and was aired live on Italian TV.

[20] Calleja debuted in the Maltese selections for the San Remo Junior Contest in 2014 with the cover version of Ronan Keating's song 'If tomorrow never comes'.