Alexius started his career teaching English Language and Literature to secondary school students. Before he joined NIE, he was a Head of Department/English Language & Literature at two local Singapore schools. At NIE, he held the following positions: Head of the Teachers Language Development Centre (2012-2015), PGDE(Sec) Coordinator (2007-2012), English Language Content Enhancement Programme Coordinator (2008-2009). He is currently Assistant Dean, International & School Partnerships with the Office of Teacher Education.
Although the bulk of his work revolves around teacher education programmes, Alexius remains very much in touch with schools. He continues to engage teachers through workshops, talks and research projects. He is currently the Chairperson of the School Advisory Committee for Woodlands Ring Primary School.
Alexius received the NIE Excellence in Teaching Commendation in 2006, 2008, 2010 and 2014. He was also awarded the NTU Nanyang Award for Excellence in Teaching in 2010.