In 1822 Macdonald was sent to St Kilda (all the inhabitants left in 1930, although some military are there now), an island way to the west of the Hebrides, with 108 inhabitants, only 42 adults, by the Society for Propagating Christian Knowledge. He really had a heart for St Kilda, so he knew that God was calling him there. The first time he preached it was in the school-house, a barn, to the whole island. He soon realised that none of them knew the true way to salvation. He preached thirteen times in eleven days. At the final service everyone was crying at the thought of his leaving. He thought five or six were under serious impressions and the rest of the people had a more than average interest in what would happen when they died. The whole island came to see him off.
On his return he was offered £400pa to return to the Gaelic Church, but he could not leave Urquhart. In May 1823 he was invited to speak at the London Missionary Society Conference. He had never been to London before and was very nervous about preaching in English, but he need not have been because he was a great success. He had so many invitations to speak that he had to turn down most.
In May 1824 Macdonald returned to St Kilda. He was welcomed with tears, which really moved him. He was there for two weeks with signs that the Lord was doing something. He visited the island again in 1827. (strangely the biographer does not mention any of this important event in Macdonald’s life. The remainder of this paragraph is taken from his journal). On the way to the island the weather was against them, so they had to return to Harris. They remained where they were for a few days, hoping for the weather to change, but while they were still waiting, the captain who was to take them ran out of time, having to do something else. Macdonald had been invited to minister at the Communion service at Uig, so he decided to go there, arriving the day before the service. There had been a revival going on for some time, and there were 7,000 at the Communion. He preached on the Saturday, Sunday and Monday, seeing many instances of people being touched by the Holy Spirit, or as Macdonald put it, there were showers of divine influences It is said that this was the highpoint of the revival. Like at Breabalbane it is as if the power was suddenly turned up under his ministry. On the Tuesday they stayed nine miles from Uig and the showers were evident again when he preached, and again when they returned to Harris. A man then came along who said, even though it was way out of his way, he would take them to St Kilda, but the winds were still against them, so he continued to preach when he could, taking a meeting at Tarbet on the Sabbath. Finally, the winds were fair, so they sailed for St Kilda. How providential the storms were for the blessing of the people of Lewis and Harris. At St Kilda there were signs of blessing according to the journal, but because of what was going on in Lewis it is likely that several gave their lives to the Lord there.
The same year Macdonald visited Ireland. He toured the south, speaking in a mixture of Gaelic and English. After a little practice he was able to be understood. In some places the churches were crowded out, mainly with Catholics. On one occasion, after a service where the congregation had been considerably touched by the Holy Spirit, a Catholic official got into the pulpit and tried to discredit Macdonald. On finishing his harangue he waited for some applause, but all he could see were some rather disapproving looks.
Macdonald had such a heart for St Kilda. He wanted them to have a Church, so he went around the country raising the money to build a church and manse, and in 1830 he accompanied the new minister to St Kilda.
St Kilda is no longer occupied.