Dennis was trained as a carpenter in 2004 in Thy. After a year in the Life Guards, he moved to Holstebro, where he worked as a carpenter in two different companies. In 2009, Dennis changed tracks in working life and became a pedagogue assistant at a housing offer for vulnerable young people in Ulfborg. Here he is still, working as a department head and describing his job as a social worker. In addition to working for and with the young people at the place of residence, he has taken an academy education in social pedagogy and is in a diploma education in psychiatry for 2 years.
Dennis is a Member of Holstebro City Council since the beginning of 2022 for the Social Democrats. In the city council, he is a member of the Technical Committee and the Social and Health Committee.