She had several leading roles and worked for the Famous Players–Lasky film company, appearing at least twice with Thomas Meighan and Victor Moore while being directed by Cecil B.

[1] Born to Swedish parents in Oregon, Dagmar was a stage actress in the Pacific Northwest before relocating with her family to Los Angeles and pursuing a film career.

[a] She was active in stock theater in San Francisco,[4] Seattle and Spokane, Washington, prior to becoming a film actress, often appearing in ingenue roles.

[5] In Los Angeles, Dagmar became affiliated with Constance Crawley and film director Arthur Maude.

[6] Her role in 1915's Young Romance was praised by The Owensboro Messenger, who noted that she "raises her "bit" to a place among the principals.