Born in August 1954, Nancy Rosenblum grew up in the suburbs of Los Angeles and developed an interest in photography and filmmaking at age seven. She often borrowed her father's Bell & Howell 8mm camera and spliced together short movies. After coming out as a lesbian in 1975, she attended the photography program at California Institute of the Arts (CalArts) for six years, eventually earning her Master of Fine Arts degree in 1983. During her time at CalArts, she created two photography exhibits. Her first exhibit, "Vegetables: A Reaction to Male Violence Against Women," premiered in 1979 and her second exhibit, "Some of My Best Friends... Portraits of Lesbians," was her 1983 Master's show. She also created a 3-monitor video installation about growing up in her family.
After graduating from CalArts, Rosenblum turned to video editing and filmmaking. In 1988, she edited and co-produced with Irene Pinn a documentary about lesbians called, You Can Know All I Am. From the 1980s through the mid-2000s, she worked as an editor for film and television, winning several Los Angeles Emmy Awards for her work on various news documentaries. She was also active in the gay and lesbian political movement, contributing to such organizations and publications as Lesbian Tide, Connexxus: El Centro de Mujeres, Lesbian News, Outfest and IMRU Radio; and she continued to exhibit photographs at various Southern California locations.
In 1983, Rosenblum met Mary Whitlock, who became her life partner. In August 2008, Rosenblum and Whitlock relocated to Nelson, British Columbia, where Whitlock studies music and Rosenblum continues to create art works and teach film editing at Selkirk College.