Shortly after 9 o'clock on Tuesday, Linde signed Sweden's application.
The historic moment was over in minutes.
- It feels big, serious and as if we landed in what we think is best for Sweden, Linde said before she left the room.
The application will now be submitted together with a Finnish NATO application.
This is after the decision was voted through in the Finnish Parliament and approved by President Sauli Niinistö.
The process of full membership can take several months, but is believed to go faster than usual due to the security policy situation.
An approval may, however, be delayed by Turkey, which has expressed criticism of Sweden and Finland's attitude to the organizations PKK and YPG.