Barker was born in 1812 at Chichester, Sussex, England. He arrived in South Australia in 1836 along with Colonel William Light and the crew of the Rapid. He subsequently went into partnership with Captain W. G. Field who had also served on the Rapid. After overlanding a herd of cattle from New South Wales, they took up property at Yankalilla and Finniss Flat (Fleurieu Peninsula). Barker later took up a pastoral lease in the hundred of Baldina, north of Port Wakefield. This property was held successively by his son and grandson. Alfred Barker was well known for the quality of the horses he bred. He stocked Stuart Creek run (SW of Lake Eyre South) in Winter/Spring 1859, but does not appear to have held the property long. Stuart Creek was discovered by John Mcdouall Stuart in May 1858; he named it Chambers Creek after his sponsor James Chambers, but it was subsequently named for Stuart.

Alfred Barker married Priscilla the sister of John and James Chambers 2 June 1842 in Adelaide. They had six children. Barker died 24 January 1880, age 67 at St John's Wood, near Enfield.