His father qualified as a clockmaker and he moved through Balfron, Fintry, and Comrie with his family working all the time as an engineer in the cotton mills that were developing in these parts of the Highlands.
The business grew quickly and moved to larger premises in Worroch Street, where they added boiler making to their engineering activities.
Towards the end of 1836, Tod and Macgregor opened a shipbuilding yard on the south bank of the River Clyde at Mavisbank.
At the time of the 1851 census, Margaret York, and the children from Macgregor's first marriage, were found at Meadowside House in Partick.
In around 1874, after the deaths of both David Tod and John Macgregor, the shipbuilding business was sold and renamed as D. and W. Henderson and Company.
When his funeral cortege took place, beginning at North Street, Anderston, the shops in Partick were closed, the route was lined with thousands of spectators with 'grieved countenances', the bells of the city churches were tolled from 2- to 3 o'clock’, and the flags in the harbour and on the shipping were at half-mast.
[5] His obituary states: "At the comparatively early age of 57, in the full flush and vigour of his mature manhood, after an illness of only three days, of constipation of the bowels, Mr Macgregor departed this life, at half past eleven o'clock on Thursday night, at his town residence, Meadowside House, Partick.