[1][7] In 2014, she joined the law firm MacDonald Hoague & Bayless in Seattle, became a partner in 2018 until she was commissioned as a federal judge.

[8][9] In 2017, Cartwright represented the family of Leonard Thomas in connection with claims that he had been wrongfully killed by the Lakewood police department.

[10][11][12][13] In 2020, Cartwright represented the family of 17 year-old MiChance Dunlap-Gittens, who was killed by King County police in a case of mistaken identity, and won a $2.25 million settlement.

[16] Cartwright represented several exonerees: a group of men in Fairbanks, Alaska, known as The Fairbanks Four, who spent seventeen years in prison before their exoneration for murder in 2015;[3] Paul Browning, a capital defendant, obtaining his release in 2019 after 33 years on Nevada's death row; and Rodney Wheeler, who was wrongfully accused of homicide and received a $500,000 settlement from King County in 2021.

[18][19] President Biden nominated Cartwright to the seat vacated by Judge Benjamin Settle, who assumed senior status on January 1, 2020.

[23] In addition to all Democrats on the committee, Cartwright received the support of Republican Senator Lindsey Graham.