James was born in Holliday's Cove, West Virginia, on 18th January 1855; the son of Michael Joseph and Ellen (née Kirwan) Flannery. His father Michael was the son of Paul and Bridget (née Kildea) of Cartron townland in the civil parish of Killallaghtan, near Ballinasloe, County Galway, who were married on 23rd June 1811 in the RC parish of Cappataggle in the diocese of Clonfert. The family migrated to Pittsburgh, Pennsylvania, when James was very young and he was raised in Pittsburgh. He married Harriet Rogers in 1877, and had nine children, Stella, John Rogers, Harriett, James Joseph Jr., Edith, Walter Richard, Evelyn, Edna, and Eugene Gerard.
James was educated at Christian Brothers' Parochial School. On leaving school he interested himself in the manufacture of steel in Pittsburgh and entered the employ of several different concerns. His rise in the vanadium steel industry was rapid, aided by the astute collaboration of his younger brother Joseph. In due course, he rose to become the president of the American Vanadium Company, the Vanadium Sales Company of America, the Flannery Bolt Company, the Oakland Savings and Trust Company, and the Collier Land Company.
He was a Knight of Columbus, and a member of the Duquesne Club and the Pittsburgh Athletic Association.
One of his most successful ventures was the development of the Oakland section of Pittsburgh through the construction of numerous high quality office buildings.
James died on 6th March 1920 aged 65, and he is buried in Calvary Cemetery, Pittsburgh, Pennsylvania [Section B, Lot 4].
[his portrait is illustrated above; courtesy of "The book of prominent Pennsylvanians" (Moore, 1913)]