- Son of former Admiral of Castile Fernán Sánchez de Tovar.
- Married Elvira Leonor Téllez de Castilla, a niece of King Enrique II, and daughter of Prince Tello of Castile, Lord of Aguilar de Campoo, Vizcaya, Castañeda and Lara. Had one son, Fernando Sánchez de Tovar, who shared the same name as his grandfather.
- Shares the same name with his uncle, Juan Fernández de Tovar, who was killed by Pedro I of Castile in 1366.
- His career as Admiral was extremely short. Succeeded his father, who died from the plague at the siege of Lisbon (1384).
- During his appointment as Almirante of Castile, naval affairs were taken over by Per Afán de Ribera, a skilled mariner. At the time it was not unusual for Admirals not being actually in charge of the fleet.
- Died at the Battle of Aljubarrota, where Castile suffered a severe defeat (1385).