Johnsen started working at the offices of Stig Anderson’s publishing company Sweden Music and the record company Polar Music in September 1969.
After a while she became Anderson's secretary. A few years into the 1970s she had become a key figure in the organisation and acquired the title of Vice President of Polar Music.
During the ABBA years she handled the contacts with the many labels around the world who released the group’s records. She also became ABBA’s personal manager, dealing with the press and accompanying them on their tours and promotional trips. In the process, she became a personal friend of the individual members as well. In 1980 she married journalist and photographer Anders Hanser, whom she met while he was covering ABBA for a radio series.
After ABBA’s break-up, Johnsen continued working for Sweden Music and Polar for a couple of years. In 1987 she started her own company, Music & Artist Service Görel Hanser. She and her staff are mainly occupied with handling the practical details concerning Benny Andersson’s work, including the Andersson/Ulvaeus musicals. On behalf of Björn Ulvaeus and Andersson she also handles all the questions concerning ABBA-related business. In April 2011, she represented ABBA at the 25th Anniversary of the Official International ABBA Fan Club in Roosendaal, the Netherlands.
In 2018, Görel received a Swedish Grammis Award for her work with Stikkan Anderson and ABBA over the years.