Moseley was born in Gawler, a son of Alice Moseley, née Maynard and Henry Jackson Moseley, who emigrated with two brothers aboard Tam O'Shanter which arrived in 1836 as part of the First Fleet of South Australia, and is remembered for building the Pier Hotel, Glenelg. He was educated at J Mordey Mitchell's Glenelg Educational Institution, and on leaving was drawn to pastoral development, and around 1867, with his brother Thomas left home with a combined capital of £800, which they put into a property, which might have been Coondambo Station, some north-west of Port Augusta. They were defeated by drought and lost everything, and returned to Adelaide. For a time he managed Yadlamalka and Black Point stations, and in 1880, having raised sufficient capital, returned to Coondambo, and went into partnership with the owner Robert Bruce. They were the first in northern South Australia to employ wire netting to keep outwild dogs and the rabbit pest, which they exterminated by fencing off the watercourses and waiting for a heatwave. He was also the first to sink a well in the north-west country. They sold Coondambo by auction at White's Rooms in 1879, realizing a substantial profit, then Moseley took up Yadlamalka Station, of, which he purchased in 1888. Shortly after 1900 Moseley took over the neglected Yardea, Paney, Pondana, Yarloo and Carcuppa stations in the Gawler Ranges, turning them from degraded land overrun with rabbits into a profitable sheep run. He ringed the properties with of wire netting fencing, in conjunction with Andrew Tennant's adjacent Thurlga Station, which he later purchased. Within twenty years had disposed of them at a substantial profit. He was also the first pastoralist to pipe water into the sheep runs. In 1910 he left the land and was elected to the House of Assembly seat of Flinders, which encompassed Eyre Peninsula, which he knew well, and was regularly returned until he retired 22 years later. He was known as a stalwart fighter for the "man on the land", particularly those in the outback. He was known as the father of the Tod River scheme for his promotion of that reservoir. His remains were interred at the Mitcham General Cemetery.
Family
Moseley married twice and had a son James Moseley of Keith and four daughters. They had a home at Prescott Terrace, Rose Park.