Here are the heights of the stars of Hawaii Five-0, as listed on IMDB — which is the best we can do without following them with a tape measure!
Alex O'Loughlin who plays Lieutenant Commander Steve McGarrett is the tallest of the cast at 6' 3/4".
Daniel Dae Kim (Chin Ho Kelly) and Grace Park (Officer Kono Kalakaua) tie for third place at 5’9”.
Scott Caan who plays Detective Sgt. Danny Williams stands at a diminutive 5’5.”
Looks like Scott was standing on a box for this group shot!