Angus had become one of the wealthiest men in Montreal, and he was also well known for his philanthropic activities and generous donations to the causes to which he allied himself. He was President of the Royal Victoria Hospital, Montreal, and in 1906 co-founded the Alexandra Contagious Diseases Hospital, serving as a governor. He was president and Governor of the Fraser Institute Free Public Library; vice-president of the Victorian Order of Nurses, Governor of McGill University (to which he donated one of his more considerable sums) and Governor of the Montreal General Hospital. He was a director of the Charity Organization Society, which he generously funded.