Justin’s general research interests are in colonial literature, travel writing, and the relationship between religion and imperialism. His articles have appeared in Literature and Theology, Studies in Travel Writing, Victorian Literature and Culture, Scottish Geographical Journal, English in Africa, and Journal of Victorian Culture. Justin’s first monograph, entitled Livingstone’s ‘Lives’: A Metabiography of a Victorian Icon, was published by Manchester University Press in 2014. This book examines the missionary-explorer’s changing posthumous reputation, particularly in relation to the British imperial project. 

In 2019, Justin completed a digital project, Livingstone's Missionary Travels Manuscript (1857): A Critical Edition, published by the digital museum and library, Livingstone Online. This edition provides access to critically encoded and annotated transcriptions of the 1100 page hand-written manuscript of Livingstone's major work, and contains a range of critical essays on topics including the publication and composition of Missionary Travels; the patterns of revision and redaction that shaped the book; and the theory and practice of digitally editing the expeditionary record. The edition was peer-reviewed by the Modern Language Association's Comittee on Scholarly Editions; in 2020, it was was awarded the seal of the CSE designating it as an MLA Approved Edition.

Justin is currently embarking on a new monograph, which aims to examine the considerable range of fictional material produced by the Victorian explorers of Africa; this project is provisionally entitled, The Fiction of Exploration. 

Justin studied as an undergraduate and postgraduate at the University of Edinburgh. He completed his PhD in 2011, funded by the Helen Philip Memorial Scholarship and the Carnegie Trust for the Universities of Scotland. Before joining the School of Arts, English and Languages in 2016, he spent a year at the Institute for Collaborative Research in the Humanities. From 2012-2015, he worked at the University of Glasgow as the Lord Kelvin Adam Smith Research Fellow in Critical Studies.