A poor Welsh miller's son from Haverfordwest, Pembrokeshire, James ran away to sea in 1732 and by 1738 was commanding his own ship and serving in the West Indies. Nine years later, in 1747, he joined the East India Company and was appointed commodore of its Bombay Marine naval forces four years later. In February 1756, he supported the capture of Gheriah (now Vijaydurg) by Colonel Robert Clive and Admiral Charles Watson, and was active in numerous skirmishes against the French, helping to consolidate the British position in India.