The Starfleet Medal of Honor was an award, one of Starfleet's highest commendations. It recognized valor and bravery in action "above and beyond the call of duty."
Captain James T. Kirk was a recipient of this medal prior to 2267. (TOS: "Court Martial", "This Side of Paradise") Kirk's emotional reaction to seeing the medal, after removing it from the safe in his quarters, seems to have helped him shake off the effect of the Omicron spores.
Lieutenant Commander Data was also a recipient of this medal prior to 2365. (TNG: "The Measure Of A Man")