Tharanga began employment at LCBL in 2004 as a Trainee Tea Executive. In 2005, was appointed as a Junior Tea Executive, handling the sale of high, medium, and dust catalogues. In 2006, Tharanga took over responsibility for the leafy catalogue.

In 2014, Tharanga left LCBL to join Mercantile Brokers as Manager – Tea Department, overseeing the leafy catalogue. In 2016, was promoted to Senior Manager, and subsequently to Per-Pro in charge of the Leafy Catalogue.

In September 2025, Tharanga rejoined LCBL, taking responsibility for the sale of Ex-Estate teas.