In 2019, Castañeda began portraying Diego Hargreeves in the Netflix series The Umbrella Academy.

[3][a] He returned to the United States when he was 14 and attended William Workman High School in California.

[5] He played various minor roles in a number of productions, such as End of Watch, and also acted as a main character in a short film Maddoggin', which won the audience award at the NBC Universal Short Cut Film Festival.

[5] In 2013, he landed a role playing Jorge on ABC Family's TV series Switched at Birth.

[4] In 2017, he was cast in his most prominent role yet playing Diego Hargreeves / Number 2 in The Umbrella Academy,[9] which was released on Netflix in February 2019.