He was the younger son of Colonel Alexander Saunderson, who served as the Tory Member of Parliament (MP) for Cavan, and The Hon.

Saunderson was educated abroad, mostly in Nice by private tutors, and inherited his father's County Cavan estates following his death in 1857.

Other than opposing the disestablishment of the Irish church in 1869, he otherwise gave little sign of political interest or activity at this stage.

Saunderson became known for his uncompromising speeches in the House of Commons, and he was nicknamed "the Dancing Dervish" by friends and opponents.

[4] Saunderson had entered the Cavan militia (4th battalion Royal Irish Fusiliers) in 1862, and was made a major in 1875.

[2] In March 1893, Saunderson was one of the signatories of the manifesto of the Ulster Defence Union, launched to organise resistance to the Second Home Rule Bill of 1893.

[8] Together the couple had four sons (two of whom were British Army officers) and a daughter, including:[9] In his private life, Saunderson was well known as a keen yachtsman, and his character was deeply marked by stern religious feeling.