In 1798 Joseph Macdonald subscribed £25 from Demerara to the establishment of the Northern Infirmary, Inverness. This was a substantial sum suggesting that he was a prosperous settler in the colony.
In 1800 he was on Dochfour Estate, from where he wrote 5 April to Hector Macdonald Buchanan (an Edinburgh lawyer), having found a situation on George Inglis's estate for a Ewen Mackinnon who had arrived in Demarara with a letter (presumably a letter of recommendation) from Buchanan:
. . . his wages [will be] but small (only fifty pounds sterling per year and board). I however thought that considerably counterbalanced by his being the first year so very near hand myself and where his board would be of the best kind . . . I have not the least doubt if he goes on as he has done since his arrival of procuring him a salary of two hundred pounds per year in the course of eighteen months more. [NRS, GD47/684]
Macdonald encouraged Buchanan to recommend other suitable young men.
Macdonald was a signatory of an address to Thomas Cuming in 1812 and one of those who contrinuted to a presentation of a sword to Brigadier-General Murray in 1813. He was also one of the stewards of the short lived Berbice Agricultural Society, along with John Ross, Robert Taitt and Gilbert Robertson [Timehri: the journal of the Royal Agricultural and Commercial Society Volume 6 p74].
In 1811 there was action to force a judicial sale of his property, the western half of plantation no 36 on the Corentyne Coast, Berbice [London Gazette 24 Nov 1811] but this was still in his possession in 1817, when he made a return for 29 slaves. Macdonald also made the return for Jane Macrae, a free woman of colour, who owned two slaves. [Slave registers]