Berg previously served as Oslo City Commissioner for transport and the environment from 2015 to 2021, when she resigned following a confidence vote.

[9] Following the 2015 local elections, she was appointed city commissioner for transport and the environment and deputy governing mayor in Raymond Johansen's cabinet.

[10] Berg was on parental leave from 2 January to 3 August 2020, and her duties as city commissioner was covered by the party's deputy leader, Arild Hermestad.

[12][13] In February 2021, she announced that she intended to create a zero-emissions zone within the city where petrol and diesel cars would be prohibited.

[20] Berg's father, Khanh Thanh Nguyen, moved from Vietnam to Norway as a 13 year old in 1968, after becoming paralyzed after a fall.

Her mother, Mari Ann Berg, is a local politician for the Socialist Left Party in Oppegård (now Nordre Follo).