After small appearances in TV shows and films such as Early Edition, Turks, The Watcher, and Ghost World, he was cast in two episodes of Third Watch.

[7] He made many TV appearances between 2005 and 2012, including major network shows such as ER, Grey's Anatomy, Criminal Minds, Without a Trace, CSI: Miami, Prison Break, White Collar, Lost, and Dollhouse.

That year, he also portrayed Hans Schroeder in the HBO series Boardwalk Empire, and an orderly at the mental hospital in Shutter Island.

In 2011, he was in the television pilot for Body of Proof, and had a full role in Adult Swim's comedy horror TV series The Heart, She Holler, as Sheriff.

[11] In 2020, Sikora portrayed Frank Cosgrove Jr. on the third season of the Netflix crime drama Ozark, released on March 27, 2020.