After taking his degree he returned to Scotland, and entered the Firm of Messrs. David Colville and Sons, Ltd., of the Dalzell Steel Works, Motherwell. At first he occupied the position of Assistant Works Manager, and later became one of the Directors of the Firm. Those associated with him in a business capacity have characterized him as 'an exceptionally able and clear-headed man of business.' In collaboration with Professor Barr, he carried out an important and valuable series of tests on High Tensile Steel in the Glasgow University Engineering Laboratory. He designed a Slide Rule for the calculation of weights and areas of steel, which is of great assistance to those employed in Rolling Mills. In the designing of new Plant his experience was of great benefit to the Firm. He was a member of the Iron and Steel Institute, and an Associate member of the Institution of Civil Engineers, and a member of the West of Scotland Iron and Steel Institute, of which at one time he was a Vice-President. His relations with the men at the Works were always of the happiest, and one of his colleagues wrote to Mrs. Lusk on the night when the news of his death reached home,--'There will be many sad hearts in the Works tomorrow.' James Lusk was not a man who liked publicity in any form, nor yet one who cared to talk much of the deepest things. But after his Father's death in 1913, he loyally tried to carry on the tradition of service which was handed down to him. The Council of the Lanarkshire Christian Union passed the following minute in February, 1916:--'We desire to minute our great sense of loss which we have sustained in the death of our esteemed member of Council, Captain James Lusk. He was a man of the utmost integrity, who at all times exhibited a true Christian character. His was a life not of words but of deeds, and he made the great sacrifice on the field of battle in the performance of his duty. "Greater love hath no man than this, that a man lay down his life for his friends."' In the Obituary columns of the _Temperance Leader_ of January 15th, 1916, it is noted that 'Captain Lusk .... has been a life-long abstainer, and a member of the Scottish Temperance League since his boyhood.... In the case of Captain Lusk and that of other brave lads who have fallen in this cruel war, it has been clearly demonstrated that a man may be a brave soldier and an efficient leader on the battle-field without the taint of alcohol.' James Lusk probably felt that the young men and boys of the great busy town of Motherwell had a special claim upon his time and thoughts. He was President of their Dalzell Highland Pipe Band, and also a Director of the Junior section of the Motherwell Young Men's Christian Association. What his fellow-workers thought of him must be told in the words of a fine 'Appreciation,' contributed by one of them to their _Young Men's Magazine_, January, 1916:--