On May 21, 2018, Cryer was featured in the premier of Episode 1, Season 9 of genealogy program Who Do You Think You Are? Cryer's journey took him from America to Scotland as he uncovered the dramatic tale of his ancestor James Adams, a Scottish Covenanter soldier who was captured during the Battle of Dunbar in 1650, and endured horrific conditions as a prisoner. He was then transported to America an indentured servant to work at the Saugus Iron Works at Lynn, Massachusetts. As part of his research for the episode, Cryer visited the site of the Battle of Dunbar, Durham Cathedral in Durham, North East England – where surviving Scottish prisoners were held until they were indentured – and the Saugus Iron Works national historic site. Cryer said: "Seeing the resilience of my family over centuries, you can see the legacy he left. I can't help but feel lucky...clearly, the resilience of my family, that spine of steel, was not something that came from nowhere. Moving forward, I'm going to take James Adams' strength as my inspiration and know that when you go through very, very difficult times, if you can turn around and help the people around you who had it even worse, that's real strength. And I aspire to be one of those people."
On November 16, 2018, it was announced that Cryer had been cast as Lex Luthor on The CW's Supergirl in a recurring role, starting in the fifteenth episode of Season 4, titled "O Brother, Where Art Thou?". He is set reprise the role in the Batwoman and The Flash episodes of the Arrowverse crossover Crisis on Infinite Earths.