Women and many people of color continue to be minoritized in STEM and notably in physics. We conducted two studies demonstrating that exposure to counternarratives about "who does physics" and "why one does physics" significantly increases high school students--especially women's--physics-related career intentions. These counternarratives facilitate making connections with students' career plans and help in sensemaking causes for the continued minoritization of women in physics. Two separate studies measured the impacts of these interventions on students' physics-related career intentions: first, with an intentionally selected group of teachers (10 teachers, 823 students) across regions and contexts in the U.S.; second, with a randomly sampled group of teachers (13 teachers, 1509 students) from three regions that also included a comparable control group. The results clearly show the importance of exposure to counternarratives in the development of high school students' career interests, particularly for women and minoritized racial or ethnic groups, and that such counternarratives may help to address systemic issues of underrepresentation in STEM.