Sean Michael O'Bryan (born September 10, 1963) is an American film and television actor. He co-starred with William Ragsdale on the short-lived series Brother's Keeper.

Early television work includes guest roles on television series in Married... with Children, MacGyver, Northern Exposure, Cold Case, Diagnosis: Murder, Quantum Leap, Murder, She Wrote, Chicago Hope, Roswell, Roseanne, Criminal Minds, The King of Queens and Dexter. More recent television guest star credits include CSI, Bones, Melissa & Joey, Lie to Me, Hot In Cleveland, The Mentalist, Leverage, Glee, NCIS: LA, Superstore, and 9-1-1: Lone Star.

He's had recurring roles on TV series including  the sitcom Pig Sty, Six Feet Under, Abby, The Middle, and Love, Victor. He had a major recurring role as Bill Blackham on Persons Unknown.

His film credits include Chaplin, Crimson Tide, Phenomenon, Exit to Eden, Out to Sea, Big Fat Liar, Deck the Halls, I'll Be Home For Christmas, Yes Man, Vantage Point, both Princess Diaries films, Playing for Keeps, Olympus Has Fallen, London Has Fallen, Table 58, Mother's Day, Searching, and Rust Creek.