No, Michael Rosenbaum has not retired from acting. He has continued to work in both film and television since leaving Smallville in 2008. He has appeared in films such as Guardians of the Galaxy Vol. 2 and The Good Wife, and he has also starred in the television series Impastor and The Grinder.
Rosenbaum has also been active in the podcasting world. He hosts the popular podcast Inside of You with Michael Rosenbaum, which features interviews with other actors and celebrities.
In a 2016 interview, Rosenbaum said that he does not plan to retire from acting anytime soon. He said that he loves acting and that he is still finding new challenges and opportunities in the field.
So, if you are a fan of Michael Rosenbaum, you can rest assured that he will continue to entertain you for years to come.