The Mazelly-Miller family has a long heritage in the British circus and fairground, descending from the Shufflebottom and the Fossett families. The family was first established by Elizabeth Fossett, sister of Sir Robert Fossett (1824-1875), and Thomas L.H. Miller (1842-1908). Elizabeth and Thomas had a son Henry Miller (1817-1904) who married Ellen Bishop (1872-1950), sister of Rosina J. Shufflebottom (1868-1937), neé Bishop. Ellen and Rosina's father was Richard Bishop (1843-1918), the son of James Bishop and Elizbeth Uren. James was known as ‘the oldest showman in England’ when he died at age 88. James was the uncle of Selina Young who famously tightrope walked across the Thames. Ellen and Rosina's mother was Ellen Lismore (1846-1924), daughter of Walter Lismore (1824-1869) who was also a travelling showman. Ellen Lismore was the only survivor of a tragic firework fire that killed all her family in 1863.

Henry and Ellen had a daughter Mazelly White (1902-1988) neé Miller/Webb, born two years before his father's untimely death. His widow Ellen remarried William Webb.

Mazelly had six siblings, including showman Henry Miller (1903-1955) and Richard Miller who served in the Royal Marines during World War One and died at the Battle of Coronel in 1914 aged 19.

Mazelly travelled the fairgrounds with her family until she married William John White (1904-1988), brother of Samuel Vere White (1902-1964) who appears to have been a bare-knuckle fighter.