Beaver in 2006 joined the cast of the HBO drama "John from Cincinnati" while simultaneously playing the recurring roles of Bobby Singer on "Supernatural" and Carter Reese on another HBO drama "Big Love", appearing at least once a season on "Supernatural". He then took on the role of Sheriff Charlie Mills in the CBS drama "Harper's Island". He has recurred as the gun dealer Lawson on "Breaking Bad" and its prequel "Better Call Saul", and played Sheriff Shelby Parlow for three seasons on FX's "Justified".