Sister Monica Joan (birth name, Antonia Keville) was one of the first to qualify as a nurse midwife in the United Kingdom. She is portrayed by Judy Parfitt.
Sister Monica Joan was born in a grand estate, and was born into a very well-to-do family who didn't approve of her pursuit of a midwifery career nor did they support her in her subsequent entry into the religious life. Her difficulties with her family have been referred to frequently throughout the series although she does reconcile with her nephew and his family in Season Two.
As a young girl. Sister Monica Joan, then named Antonia, was well educated and found solace in reading books, particularly the bible. She also loved sweets very much. Antonia had a very difficult relationship with her mother, the reasons for which are not explained fully, but it is hinted that Antonia's interest in religion and desire to become a nurse contributed to the strain. Later in life, Sister Monica Joan recalled that her mother would call her "stupid" and say she was "too tall". She would go on to say that their tumultuous relationship "did not grieve" her when her mother was still alive, but once she died, she found that she missed her dearly, and still loved her deeply, despite their differences.
When Sister Monica Joan entered into the religious life she had not a penny to her name, perhaps because her family disowned her. In Series 6, she recalls that when she took her final vows and had to wear a wedding dress to commemorate the day, she was deemed too tall to have need of high heels. When her mother died she left her some of her jewellery which was given to the Order when she took her final vows in 1904. These were the jewels that Sister Monica Joan was accused of stealing in the Season One finale but Mother Jesu tells the court she gave her the jewels as "balm for an old wound". Later, during a time when the Sister was very confused and upset, Sister Julienne brought out the jewels and grounded Sister Monica Joan back to her surroundings, calming her greatly.
Sister Monica Joan has a love of literature, astrology, and sweets, particularly cake. When Jenny first arrives at Nonnatus House, she is quick to show off her love for astrology, and to insist that Jenny consume a whole cake with her.
Due to her old age, Sister Monica Joan often gets confused. At the end of the first season, she is taken to court for theft, and during this time, some jewellery is found amongst her belongings, but it turns out the jewellery had belonged to her mother, and Mother Jesu told the court that Sister Monica Joan recognised neither the jewels nor her petty thefts due to her fragility, and the charges were dropped.
In the 2014 Christmas Special when Shelagh prepares for her wedding to Dr. Turner, Sister Monica Joan expresses sorrow at having lost Sister Bernadette. She speculates that Shelagh threw away a life of religion for the pleasures of physical love, "confusing" what she was truly in need of. Sister Julienne calms her down, saying it is normal to miss their Sister, but that they must respect her choice. At the end of the episode, Sister Monica Joan gives Shelagh her prized hyacinth flowers to walk down the aisle with.
Sister Monica Joan often fears she is old and useless and expresses a desire to help. In one episode in Season Four she gets her chance when a heavily pregnant woman in labour arrives at Nonnatus House looking for help and since the only available midwife, Trixie, has passed out from drinking too much alcohol, Sister Monica Joan has to take matters into her own hands. She takes the woman to Dr. Turner's surgery, where Shelagh helps to deliver the woman's child, and the woman shows the elderly nun her gratitude by naming her baby girl Monica, and she is deeply moved by the gesture.
In Series 5, when Sister Evangelina passes away, Dr. Turner tells Sister Julienne that because the Sister died suddenly and unexpectedly, there will need to be an autopsy. Sister Monica Joan was devastated at the prospect, saying that to do an autopsy would "maim" Sister Evangelina for all eternity. Thankfully, the autopsy did not occur. At the funeral, Sister Monica Joan laid Sister Evangelina's shoes on the coffin, saying they deserved a rest, as their Sister does.
In Series 7, Sister Monica Joan begins to show worrying signs that her eyesight is failing such as squinting her eyes, relying on a very strong magnifying glass to read, and crouching down directly in front of the television. Sister Monica Joan is eventually diagnosed with cataracts and is warned that unless she has surgery she will go blind. Sister Monica Joan is afraid to undergo the procedure at first, but Fred manages to persuade her to agree to the surgery.
- "Venus and Saturn are now in alignment. It is entirely appropriate that you should appear."
- - Sister Monica Joan's first words to Jenny
- "And I do not like my greens, yet they are very good for me."
- - Sister Monica Joan's words of advice to Phyllis Crane
- "I find that two opinions are always better than one. Particularly if one is mine."
- - Sister Monica Joan