A store in George Street, Sydney was taken over by Spark and by 1825 he was chartering ships for the coastal trade. He was also an agent for country settlers and later became the Managing Director of the Bank of Australia. He also owned an estate at Cooks River.
Spark's favourite residence was his farm at Cooks River however in 1829 he was at the Hunter Valley property when it was robbed by bushrangers Richard Brown, Patrick Corcoran, Richard Turnstyle and Andrew Cullen. In an attempt to keep the bushrangers at bay, he fired through the door at them.  The bushrangers were later captured and executed at Maitland.
Later A.B. Spark was to increase his holdings in the Hunter region to over 6,000 acres. Many convicts were assigned to him at the Hunter River. One of them was Benjamin Hall the father of one of Australia's most famous bushrangers......
Alexander B. Spark was a Magistrate and a friend of James Mudie. Some of the convicts assigned to A.B. Spark at the Hunter River were re-assigned or at least worked on James Mudie's Castle Forbes estate and James Mudie was known to visit A.B. Spark on his farm at Cooks river. Later after James Mudie's returned to England, Spark became a private distributor of Mudie's slanderous The Felonry of New South Wales.
In 1834 he commissioned John Verge to design Tempe House.
In April 1840 Alexander Brodie Spark married Frances Maria (nee Biddulph), the widow of Henry Wyatt Radford of Ravensfield Station a 2000 estate at the Hunter River. Until 1847 Ravensfield was occupied by William Geddes however Spark advertised it for lease in May of that year. There were several buildings on the property including a cottage, houses and a malt kiln and 'every convenience for a dairy farm' all surrounded by strong fences.
In the 1840's financial depression Alexander Brodie Spark came into financial difficulties and was declared insolvent in 1844.
Alexander Brodie Spark died at Tempe on 21 October 1856.