He has worked in both film and television, gaining his first leading role in Pandora's Box, a 2009 film adaptation of an Osamu Dazai novel.

[2] In 2011, he received the Marcello Mastroianni Award for Best New Young Actor at the Venice Film Festival for his work in Himizu along with his co-star Fumi Nikaidō.

[3] He appeared in Shinji Aoyama's 2011 film Tokyo Park,[4] Koji Wakamatsu's 2012 film The Millennial Rapture,[5] and starred in Gakuryu Ishii's 2012 film Isn't Anyone Alive?

[6] Sometani married actress Rinko Kikuchi on December 31, 2014.

In October 2016, Kikuchi gave birth to their first child.