His mother was Jean, daughter of Sir William Hay of Locherworth, Midlothian.
Sir Alexander was one of the envoys sent by King James II, on 27 July 1451, to treat with England, and with his fellow commissioners he signed a truce for three years on 14 August 1451, in the Church of St Nicholas, Newcastle-upon-Tyne.
Lord Home married twice: (1) Mariotta (or Marion), the daughter and co-heiress of John Lauder (d.v.p.1421),(son of Sir Robert de Lawedre of Edrington and The Bass (d. 1425)), by John's spouse Katherine, heiress to her father William de Landells and his wife Jonet.
A Papal dispensation by Pope Martin V was issued on 11 April 1426 at St Peter's, Rome, for Alexander de Home and Marion Lauder (de Lawedre) to marry, notwithstanding that they are related doubly in the fourth degree of consanguinity.
They had further children: His grandson Alexander, the future 2nd Lord, was a leader of the rebels who defeated King James III of Scotland at the Battle of Sauchieburn.