Harry Tinson was the son of Robert Tinson Holman (1823-1906), founder of the mercantile firm of R.T. Holman Limited of Summerside, Prince Edward Island. Harry was born on 17 March 1875 and was educated at schools in Summerside. When he left school in 1892 he joined the family firm and worked in various junior capacities in the business until the firm was incorporated in 1906 and he became treasurer of the company. On the death of his father the same year he was appointed president and joint manager with his brother James LeRoy Holman. He continued as president and manager until 1945. The firm grew under his administration eventually becoming one of the major independently owned retail establishments in the region. Under Harry's management the firm embarked on an ambitious program which saw the introduction of mail order catalogue sales as well as operation of radio station CHGS (Call - Holmans Guarantee Satisfaction) from the store premises.

During the fox ranching boom in the area Holman owned or was involved with several fox ranches. He was for some time president of the Hall Manufacturing and Cold Storage Company and was also a vice-president of the Pioneer Publishing Company.

Holman was keenly interested in the Prince County Hospital and served for twenty-five years as president of the Board of Trustees. He was also vice-president of the Summerside Board of Trade and an active supporter of tourism activities. Other civic organizations in which he was active included the Summerside Golf Club and the Curling Club.

He lived for about five years following retirement from many of his business
interests and died following a heart attack on 20 April 1950. The firm of R.T. Holman Limited continued to be operated by his sons Alan H. Holman and Harry T. Holman Jr. until the 1980s.