Macklin was born in
West Harnham, near
Salisbury, on 23 September 1864, the son of James Macklin (senior) and his wife, Sarah. When the national census of England was taken in April 1871, James Macklin (senior) was described as a jeweller's shopman, living in West Harnham with his wife, four daughters and three sons. He later went into business as a cutler at No. 7 Catherine Street in Salisbury, and the business became well known as James Macklin & Son, watchmakers and jewellers, silversmiths and cutlers. When the census was taken in April 1881, Macklin was described as an assistant in his father's business, living and working at No. 7 Catherine Street with his father (now described as a cutler, employing one man and one boy), mother, three sisters, two brothers and nephew. Eventually Macklin took over the running of the business. When the census was taken in April 1891, he was described as a jeweller, living and working at No. 7 Catherine Street with his wife and a domestic servant. At the April 1911 census, he described himself as a retired jeweller, living at
Watersmeet in Harnham with his wife, two daughters, son, and domestic servant. Macklin demonstrated significant business acumen. "Succeeding to an old-established business, which represents the last of the old cutlery trade, for which Salisbury at one time had a considerable reputation, he considerably extended its scope, and retired very early in life to a beautiful home he created for himself at East Harnham. ... Acquiring considerable property in the old village, which was incorporated into the borough [of Salisbury] in 1904, Mr. Macklin readily gave up land to improve the roads, and generally devoted himself to the interests of the parish. He has lately given considerable attention to agricultural pursuits, in conjunction with his son, and is in occupation of a large farm at
Tytherley." In the years that followed, he concentrated on his farming interests. ==Mayor of Salisbury==