She is the Moderates traffic-politics spokesperson.
In October 2010, Rosencrantz started her work in the Riksdag as replacement-minister.
And after two weeks she became a full member of the Riksdag, this after minister Anna König Jerlmyr became vice mayor in Stockholm by which time she left her place in the Riksdag.
She became a suppleant for the finance committee and civilian committee.Since 2013, she is a suppleant in the European Commission as well.She has been district president for the Moderate Party Youths in Stockholm.
Rosencrantz has worked for the European parliament.