Alden was a male Human Starfleet officer in the 23rd century. He served in the sciences division aboard the USS Enterprise in 2265, under the command of Captain James T. Kirk, during the historic five-year mission. He was one of the ship's communications officers.
In that year, Alden was manning the helm as the Enterprise approached the edge of the galaxy in preparation for an exploratory expedition into extragalactic space, when he was relieved by Lieutenant Gary Mitchell, subsequently taking over the communications station. Later, Alden assisted Lieutenant Lee Kelso in adapting equipment and technology from the Delta Vega lithium cracking station, in an attempt to repair damage done to the Enterprise during an encounter with an extremely powerful force field encountered at the galaxy's edge. (TOS: "Where No Man Has Gone Before")
The uniform Alden wore had one braid for the ranks of ensign to commander; therefore, his rank cannot be determined from his uniform. His position as communications officer in "Where No Man Has Gone Before" was from the script.  Publicity material referred to him as the communications officer, but his responsibilities did not appear to entail those of a comm officer. Nyota Uhura's biography in DC Comics' non-canon "Who's Who in Star Trek 2" states that Uhura succeeded Lt. Richard Alden as chief of communications on stardate 1313.2.
Alden was played by actor Lloyd Haynes, one of many African-American actors who read for "Where Man Has Gone Before" due to the fact that Gene Roddenberry agreed with a certain long-standing NBC policy: that the network's "creative associates" make a concerted effort to cast performers of ethnic minorities. As such, Alden was one of the first important roles, in a network television pilot, to be played by an African-American actor. (Inside Star Trek: The Real Story, pp. 75-77) Haynes was brought in to audition for the part by director James Goldstone, a friend of the actor. (The Star Trek Interview Book, p. 105)
Communications officer Alden refuses to be awed by the demanding task of establishing and maintaining contact across vast distances. One of the youngest members of Kirk's staff, he also is one of this talented group's most respected technicians.