The initial EP featured the single "Blood // Water", which appeared on several Billboard charts in the United States and Canada.

When he was 3 years old, his family moved to a Jewish neighborhood in Toronto, Ontario, where his maternal relatives lived[5][6] (he holds dual citizenship of both countries).

[14] He had also released two new singles, "Blood // Water" (a song about political corruption that would go on to appear on multiple Billboard charts) and "Thoughts & Prayers", which offered a critique of American gun laws in the wake of the shooting at Marjory Stoneman Douglas High School in Parkland, Florida.

[17] Also in June 2018, grandson was featured on Mike Shinoda's song "Running from My Shadow", taken from his debut album Post Traumatic; the track was released also with an accompanying music video in May 2018.

[8][23] In late May, grandson released a cover of Rage Against the Machine's "Maria", a song featured on the 1999 album The Battle of Los Angeles.

[24] In June 2019, he won the SOCAN Songwriting Prize for his song "Blood // Water",[25] while in September 2019 the singer released A Modern Tragedy Vol.

[27] On September 23, 2020, Grandson announced on his Facebook page that his debut full-length album Death of an Optimist would be released on December 4, 2020.

In September 2024, it was announced that Grandson would be the opening act for Linkin Park on their From Zero World Tour, their first in 7 years and without former lead singer Chester Bennington following his death.