Dr. Michaela (Mike) Anne Quinn - Jane Seymour. Byron Sully - Joe Lando. Wolf - Cody. Katherine (Katie) Elizabeth Sully - Alexandra, McKenzie and Megan Calabrese. Matthew Cooper - Chad Allen. Ingrid - Jennifer Youngs. Brian Cooper - Shawn Toovey. Colleen Cooper [Cook] - Erika Flores (seasons 1-3); Jessica Bowman (3-6)