O'Connor was born in 1870, Longford, Ireland, son of land agent Matthew Weld O'Connor, and Harriet Georgina, daughter of Anthony O’Reilly, of Baltrasna, County Meath.
He had a sister, Lina O'Connor, and two younger brothers Matthew O'Connor and Myles O'Connor.
He was educated at Charterhouse School as a Junior Scholar, in Verites house, 1884-1887.
Member of Charterhouse shooting team in 1885, and placing 7th, winning the House Shooting Cup in 1885.

He passed through the Royal Military Academy in 1888 and was gazetted to the Royal Artillery in 1890.
He received Henry Wilkinson sabre number 29781 in 1889, as gift from a family member.
O'Connor was born in 1870, Longford, Ireland, son of land agent Matthew Weld O'Connor, and Harriet Georgina, daughter of Anthony O’Reilly, of Baltrasna, County Meath. He had a sister, Lina O'Connor, and two younger brothers Matthew O'Connor and Myles O'Connor. He was educated at Charterhouse School as a Junior Scholar, in Verites house, 1884-1887. Member of Charterhouse shooting team in 1885, and placing 7th, winning the House Shooting Cup in 1885.
He passed through the Royal Military Academy in 1888 and was gazetted to the Royal Artillery in 1890. He received Henry Wilkinson sabre number 29781 in 1889, as gift from a family member.
William Frederick Travers O'Connor