James succeeded to the throne after his father, James III, was killed in a battle against rebels on June 11, 1488. The 15-year-old monarch immediately began to take an active part in government. He extended his authority to the sparsely populated areas of western and northern Scotland and by 1493 had humbled the last lord of the Isles.

Although his reign was internally peaceful, it was disturbed by wars with England. Breaking a truce with England in 1495, James prepared an invasion in support of Perkin Warbeck, a pretender to the English throne. The war was confined to a few border forays, and a seven-year peace was negotiated in December 1497, though border raids continued. Relations between England and Scotland were further stabilized in 1503, when James married Margaret Tudor, the eldest daughter of the English king Henry VII; this match resulted, a century later, in the accession of James's great-grandson, the Stuart monarch James VI of Scotland, to the English throne as King James I.

James IV's growing prestige enabled him to negotiate as an equal with the rulers of continental Europe, but his position was weakened as he came into conflict with King Henry VIII of England (ruled 1509–47). In 1512 James allied with France against England and the major continental powers. When Henry invaded France in 1513, James decided, against the counsel of his advisers, to aid his ally by advancing into England. He captured four castles in northern England in August 1513, but his army was disastrously defeated at the Battle of Flodden, near Branxton, on Sept. 9, 1513. The king was killed while fighting on foot, and most of his nobles perished. James left one legitimate child, his successor, James V (ruled 1513–42); in addition, he had many illegitimate children, several of whom became prominent figures in Scotland.

True to the ideal of the Renaissance prince, James strove to make his court a centre of refinement and learning. He patronized literature, licensed Scotland's first printers, and improved education.