After finishing her doctorate, she worked at Lund University 1999–2001 and was assistant professor of Systematic Theology/Religion and Science at the Lutheran School of Theology at Chicago 2001–2003.

For her coat of arms, she chose an oval shield design by Jan Raneke displaying triple oak leaves from her home town Herdecke's coat of arms with triple mantuan pilgrim's crosses, quartered with the flag of Scania symbolising her episcopal see of Lund.

The oak leaves are also featured on the coat of arms of Blekinge which constitutes the easternmost part of the Diocese of Lund.

[5] As Bishop of Lund, Jackelén was one of the assistant officiants during the state wedding of Victoria, Crown Princess of Sweden, and Daniel Westling, in 2010.

[10] She once again met Pope Francis when he visited Sweden during the turn of the 2016 October–November month switch, beginning the 500th anniversary of the Protestant Reformation.

Jackelén has published several works which deal with the relationship between the natural sciences and religious faith, as well as the role of religion in modern society.

In an interview with Swedish Christian newspaper Dagen, she stated that the virgin birth of Jesus is a "mythological term to explain the unique.

[23] Jackelén has spoken out against a ban on school graduation ceremonies in churches, believing a total ban on religious influences in public schools to be detrimental to the spiritual development of children, while emphasising the role of the Church of Sweden in Swedish civil society.

[24] Together with the bishops' conference she has also addressed climate change in a Bishops' letter in 2014 and again 2019, calling for the members of the Church of Sweden as well as the Swedish state to set goals to reduce greenhouse gas emissions and for Sweden to enter binding international agreements on the issue.

In the revised version 2019 she and the bishops stressed the importance of meeting the goals in the Paris Agreement[25][26] She sees a role for the Church in the existential and spiritual parts of the climate debate, such as eco-anxiety.