Ensign Harper was a male Human Starfleet officer who lived during the mid-23rd century. He served in the operations division aboard the USS Enterprise under Captain James T. Kirk, during a historic five-year mission that starship undertook. He served as one of Lieutenant Commander Montgomery Scott's engineers in 2268. Harper was played by actor Sean Morgan in his first "redshirt" role. Morgan had previously portrayed Brenner and O'Neil, both of whom survived. The novel A Choice of Catastrophes gives his first name as "Ali".