He was one of five surviving children born to Eliza Burd (née Blair) Thaw (1822–1863) and William Thaw Sr.[1] After the death of his mother in 1863, his father remarried to Mary Sibbet Copley, with whom his father had five more children.

His father was considered one of the 100 wealthiest Americans,[4] and left an enormous fortune for Thaw and his siblings upon his death in August 1889.

[6] His first job was as a railroad clerk before he organized the Hecla Coke Company with his elder brother, William Thaw Jr.

They spent much of their time in Pittsburgh, but maintained a residence in New York at 854 Fifth Avenue (which was owned by Gov.

[9] A month after his wife's death, he sold much of the art collection she had acquired over many years.