Philip Simpson Ross was born on August 24, 1827, in Belfast, Northern Ireland.

He was an accountant, businessman, and officeholder. Educated in Glasgow, he was employed as a bookkeeper at the Monkland Iron and Steel Company before emigrating to Quebec in 1851. He settled in Montreal, where he worked as an accountant at the Montreal Marine Works. In 1858, Ross left the firm to set up an independent accounting service. Around 1860 he went into partnership with his brother James, and they became the firm of P. S. Ross and Brother. In 1872, another brother, William, joined the firm. When the Canadian government implemented the insolvency act, Ross became one of its first official assignees in 1880. He also had the opportunity to become the accountant for several new corporations, e.g., Sun Mutual Life Insurance Company of Montreal and Bell Telephone Company of Canada. Eventually, three of his sons joined him, forming P. S. Ross and Sons. Ross played an important role in the development of accountancy as a profession. In 1880, he was one of the founders of the Association of Accountants in Montreal (now the Ordre des Comptables Agréés du Québec), the first organization of chartered accountants to be incorporated in North America. He became its vice-president and later president, the post he held for the next 13 years. He also served as secretary of the Canada Iron Mining Company, the Canada Insurance Union, and the Windsor Hotel Company. He was a member of the Montreal Board of Trade and Treasurer of the Natural History Society of Montreal.

In 1856, he married Christina Chalmers Dansken (1829–1911). He died on February 1, 1907, in Montreal, Quebec.