Maxwell was infefted in his grandfather's lands at Carnsalloch on 8 May 1485 and was served heir to his father in the lands of Maxwell on 29 April 1486. In 1486 he was also appointed Warden of the West Marches. In October 1488 he attended the first Parliament of James IV.[1]
The most notorious incident of Maxwell's career was his violent assault on 30 July 1508 on Robert Crichton, 2nd Lord Crichton of Sanquhar outside the court-house in Dumfries, where Crichton was holding assizes. The Maxwells and Crichtons had long competed for influence in Nithsdale and, accompanied by William Douglas of Drumlanrig, Maxwell led a considerable force into the town from the south. Bishop Lesley provided the following summary of subsequent events: "Lord Creychton was chaissit with his company frae Drumfries, and the Laird of Dalyell and the young laird of Cranchlay slain, with divers uthers, quhairof thair appeared greit deidly feid and blushed". It appears that Maxwell went largely unpunished for his part in this episode.[2]
Maxwell was one of the many Scottish nobles killed in the Battle of Flodden on 9 September 1513.[3][1]