The equivalent of the name Malcolm in Gaelic is Calum, consequently we find the names used indiscriminately in older records, and facts relating to the Malcolms and the MacCallums may be considered as referring to the same clan in the Highlands. There is a genealogy of the Clan Malcolm in the Gaelic MS. of 1450.

Sir Duncan Campbell, of Lochow, granted lands in Craignish and on the banks of Loch Avich to Reginald MacCallum of Corbarron in 1414, with the office of hereditary constable of the castles of Lochaffy and Craignish. Corbarron was bequeathed by the last of the family to Zachary MacCallum of Poltalloch. The MacCallums were in Poltalloch previous to 1652, and Dugald MacCallum of Poltalloch, who succeeded to the estate in 1779, is said to be the first to adopt the name Malcolm permanently. Dugald Malcolm of Poltalloch was succeeded by his cousin Neil Malcolm in 1778 and died in 1802.

John W. Malcolm, of Poltalloch, was created Lord Malcolm in 1896. He died in 1902.

The name Malcolm is found in Stirlingshire and Dunbartonshire as early as the 14th century.

In 1665 Charles II conferred a baronetcy of Nova Scotia on John Malcolm of Balbeadie and Grange, Fifeshire. This family also acquired the lands of Lochore and, later, lands in Dumfriesshire.