William Hall Macy Jr. (born March 13, 1950) is an American actor, screenwriter, teacher and theater director. He is well known for his role as Frank Gallagher in the sitcom Shameless.

For Disney, he played Railroad Magnate in Tall Tale, Vice Principal Gene Wolters in the 1995 Hollywood Pictures film Mr. Holland's Opus, Major Norman Caldwell in the 1997 Columbia Pictures/Touchstone Pictures film Air Force One, James Gordon in the 1998 Touchstone Pictures film A Civil Action and Dudley Frank in the 2007 Touchstone Pictures film Wild Hogs. He also voiced Satomi in The Wind Rises.

He is also the husband of Felicity Huffman.