Ross was born in Aberdeen, and entered King's College, Aberdeen after completing his studies at Aberdeen Grammar School, in 1604. About 1616 he succeeded Thomas Parker in the mastership of the free school at Southampton, an appointment which he owed to Edward Seymour, 1st Earl of Hertford. By 1622 he had been appointed, through William Laud's influence, one of Charles I's chaplains, and in that year appeared The First and Second Book of Questions and Answers upon the Book of Genesis, by Alexander Ross of Aberdeen, preacher at St. Mary's, near Southampton, and one of his Majesty's Chaplains.