Juliana entered the Sisters of Mercy in Dublin in 1840, and among the group who did their novitiate together, several were to become foundresses in various places. In 1841, a new foundation was formed at Handsworth, Birmingham, by Catherine McAuley and a group of sisters. Catherine McAuley supported the appointment (by the bishop) of Juliana Hardman as the first Superior of St. Mary’s Convent, Handsworth. Catherine McAuley and Mother M. Cecilia Marmion accompanied the founding group to Handsworth. The Hardman family was a generous benefactor to the sisters over many years. Juliana would later establish the Sisters of Mercy in Nottingham, St. Anne’s in Birmingham, and Wolverhampton and Maryvale in Birmingham. In 1844, she oversaw the construction of the House of Mercy, the church in 1847, the first poor schools in 1850, St. Joseph’s Boarding School in 1858, and the new poor schools in 1872.

Juliana was born into a staunch Catholic family whose roots were in Lancashire. She was born to John Hardman Senior and his second wife, Lydia Wareing. She was educated at home until about the age of 12, then went to Caverswall Castle in Staffordshire to be educated by the Benedictine nuns. Juliana’s sister, Mary, also became a Sister of Mercy.

Juliana knew Catherine McAuley, and it is evident that she absorbed from the foundress a clear understanding of the mission and values of the Order. An insightful biography by Barbara Jeffrey tells how the works of mercy began in Handsworth as soon as the Sisters arrived. According to Barbara Jeffrey, “The orphans were taken in, and visitation of the poor and sick was started under Juliana’s watchful care.” Education would continue to be the Sisters' primary mission, but it was not their only one; they also engaged in other works of Mercy, one of which was a House of Mercy.

The Handsworth Foundation would later become a strong centre for Mercy life and ministry. This ministry had a long-lasting impact throughout England. The sisters from this foundation would eventually become part of the Union of Sisters of Mercy of Great Britain.