Lizzie Hamilton joined the parish in East Ayrshire when she was three years old and has been closely associated ever since.
The 103-year-old was described as "remarkable" for dedicating her time over a century as she was presented with a special long service award.
Her parents registered her at Old Cumnock Old Church Sunday school in 1916.
She said she was "thrilled to bits" when the Moderator of the General Assembly of the Church of Scotland gave her a certificate during a service to mark the 150th anniversary of her church.
Rt Revd Dr Angus Morrison said it was an "absolute delight" to meet Mrs Hamilton.
Dr Morrison said: "Lizzie has a warm smile and is still deeply interested in and fully engaged with the life of the church.
"I found this remarkable lady quite inspirational and thank God for all the devoted service she has rendered across a century."
Affectionately nicknamed "Mrs Kirk" by her late husband Tommy, Mrs Hamilton still attends services every Sunday with her daughter Davina Dury.
"I was thrilled to bits when the Moderator presented me with my long service certificate - it was so unexpected," she said.
"I am so used to giving out to people, not accepting things.
"I am from an ordinary family and we have always been Church of Scotland. It is just what you did in those days but it has been very good for my life and enabled me to help people."
Revd John Paterson, who has been minister since 1994, said: "Having Lizzie and Beth together today indicates that the Church is still reaching out, informing and supporting people of all ages and there is place for every person.
"Lizzie is a marvellous woman and an inspiration that her faith, not just church attendance, has enabled her to do what she has done within the wider community."