「我的信心本身不能成就任何事情，唯有主耶穌自己要親自顯出祂的作為和能力⋯⋯終於在這光禿禿的荒原上，祂為我們擺設了豐盛的筵席。」

安妮在完成護士培訓後，曾在奧斯陸的烏勒沃爾醫院 (Ullevål Hospital) 和阿斯克的一家精神病院迪克馬克 (Dikemark) 工作。27歲時，她加入了挪威傳教聯會 (Det Norske Misjonsforbund)，開始她的傳教生涯。

1938年12月23日，安妮抵達中國北方的陝西省，開始她的傳教工作。在那裡，她度過了整個抗日戰爭和隨後的國共內戰。她身高190厘米，對當地中國人來說，這樣的身高極為罕見，她經常是當地人見過的最高的女性。然而，1949年國共內戰結束後，國民黨的失敗使得外國傳教士無法繼續留在中國，安妮於1951年被迫離開。

1952年，她前往香港，開始協調對中國難民的救援工作。次年，她與來自蘇格蘭的宣教士海倫·威爾遜 (Helen Wilson) 共同創立了一家肺結核療養院，專門為長期患病且無法自理的老年人提供服務。2013年，這家療養院——「靈實醫院」(Haven of Hope Hospital) 慶祝成立60週年，這家機構一直是香港為老年慢性病患者提供社區服務的重要場所。

安妮在挪威的事蹟通過電視節目《這是你的生活》(Dette er ditt liv) 被廣泛傳播，並使她成為挪威的國民英雄。1963年，她被授予聖奧拉夫一級騎士勳章 (First Class Knight of St. Olav)，以表彰她的貢獻。1966年6月25日，她與瑞達·貝恩森(Reidar Berntsen) 結婚，婚後繼續在香港的靈實醫院和基督教會進行她的宣教工作，直至1978年退休。

1975年12月29日，《時代》雜誌的封面故事將她列為世界「在世聖人」之一，與她同列的還包括德蘭修女 (Mother Teresa)、賽爾瑪修女 (Schwester Selma)、赫爾德·卡馬拉 (Hélder Câmara) 和瑪塔·艾爾·梅斯金 (Matta El Meskeen)。

Annie Skau Berntsen was a notable Norwegian missionary known for her impactful work in China during the early 20th century. Born in 1872, she became part of the China Inland Mission, where she dedicated her life to spreading the gospel and serving the local communities. Trained as a nurse, Annie's mission was marked by her commitment to education and healthcare. She focused on empowering women and children, recognizing the importance of nurturing future generations. Her work often involved teaching, providing medical care, and addressing social issues.

Throughout her time in China, she faced numerous challenges, including cultural barriers and the tumultuous political climate of the time. There were many times when her life was in danger and she did not know if she should live the next minute. Yet she was happy in her faith and described her faith as an island of peace in the maelstrom of hatred and destruction. Despite these hardships, her perseverance and faith drove her to make a lasting difference in the lives of many. Annie Skau Berntsen's legacy continues to inspire those involved in missionary work and social service, illustrating the profound impact that dedicated individuals can have on communities in need. This is what she said at the end of her life in 1922, “The most magnificent thing that can happen to me is to be allowed to serve Him day and night in His temple. Nothing in the world is as glorious as serving the Lord Jesus Christ!”