A millwright and union official, and known as a sportsman and humanitarian philanthropist as well as a lumberman, Grewall eventually established himself as one of the largest employers and most influential business leaders in the northern Fraser Valley, owned six sawmills and was active in community affairs serving on the boards or as chairman of a variety of organizations, and was instrumental in helping create Mission's municipal tree farm. With strong pro-labour beliefs despite his role as a mill-owner, after a scandal embroiled the provincial Ministry of Forestry under the-then Social Credit party government, he referred to holders of forest management licenses across British Columbia as Timber Maharajahs, and cautioned that within a decade, three or four giant corporations would predominantly control the entire industry in the province, echoing similarities to the archaic zamindar system in South Asia. He later ran unsuccessfully for the Co-operative Commonwealth Federation (the precursor of today's New Democratic Party) in the Dewdney riding in the provincial election of 1956.
