His grandfather was the famous Palestinian poet, Suheil Bushrui, the first Arab national to be appointed to the Chair of English at the American University of Beirut, a position he held from 1968 to 1986.

In the following year, it was announced Malarkey was cast as "Sam Foster" in Crackle's crime drama series The Oath.

That same year he starred as Captain Michael Quinn in Project Blue Book for The History Channel.

[11][12] In September 2021, it was reported that Malarkey had a recurring role as Deputy Harvey on the second season of ABC's crime drama TV series Big Sky.

[14] In February 2024, it was announced that Malarkey had joined the main cast for the second season of Netflix's conspiracy thriller series The Night Agent.