Justinna Napaljarri Sims was born in 1977 in Alice Springs Hospital, the closest hospital to Yuendumu, a remote Aboriginal community 290 km north-west from Alice Springs. She went to school at Yirara College (Alice Springs) but returned to the community in 1999 where she has lived permanently ever since. Justinna is the daughter of Elsie Napanangka Granites, a well-known artist, and the grand-daughter of Paddy Japaljarri Sims (Dec), one of the founding artists of Warlukurlangu Artists Art Association, an Aboriginal owned and governed art centre located in Yuendumu.

She has been painting with Warlukurlangu Artists since 1999, however it wasn’t until 2010 that she began to paint full-time. She paints many of her grandfather’s Jukurrpa stories, Dreamings, which include Ngarlkirdi Jukurrpa (Witchetty Grub Dreaming) and Yanjirlpirri Jukurrpa (Star Dreaming). Dreamings which relate directly to her land, its features and animals. She uses traditional iconography, while developing a contemporary individualistic style to depict her traditional Jukurrpa.

Justinna is married to Marshall Jangala Robertson and they have two sons. She also has two daughters, Vicky and Chantal from a previous marriage. As well as being a mother and an artist, Justinna also works part time in a local store in Yuendumu.