[1][2] Born in Vellore, Johnson graduated with a bachelor's degree in biotechnology at Karunya University.

Johnson graduated from University College London in 2011 and worked at the Indian Institute of Science.

[4] Johnson and colleagues developed a cell based gene therapy for haemophilia patients at the National Cancer Centre Singapore.

[5][6] Johnson developed ImSig, a network-based computational framework that facilitates the characterization of immune cells within the tumor microenvironment.

[7] Johnson's work involves multi-dimensional characterization (genetic, transcriptional, spatial and biophysical attributes) of the tumor ecosystem [8] and understanding the differences in molecular signature of immune cells [9] across tumours.