He studied at the Lyceum Grammar School and St Michael's Teachers’ Training College (1964–66).

For several years his plays have featured in Maltese Literature national curricula in high schools and University courses.

[2] Two of his plays, Pawlu Redux and Il-Festa bil-Bandieri, won the Malta National Book Award for drama.

[3] In 2011, a review in the Times of Malta called Calleja a "neglected Maltese playwright".

[4] Following in the tradition of Maltese playwright Francis Ebejer, Calleja's works depicted characters who were aspiring to a greater life but who inevitably faced insurmountable social and psychological hurdles.