Selecting the United States Air Force after graduating from West Point, he received flight training at Moore Air Base, Texas; Laredo Air Force Base, Texas; and Tyndall Air Force Base, Florida. 

He attended Randolph Air Force Base Instrument Pilots Instructor School in 1963 and served as a pilot and armament officer from March 1957 to May 1961 with the 95th Fighter Interceptor Squadron at Andrews Air Force Base, Maryland.

Prior to his arrival for duty at the Johnson Space Centre, he served as an instructor at the AerospaceResearchPilotsSchool at Edwards Air Force Base, California - from which he graduated in September 1965. As an instructor, he trained some of the men who would later become fellow astronauts. He is also a December 1964 graduate of the Empire Test Pilots School in Farnborough, England.

Col. Worden was one of the 19 astronauts selected by NASA in April 1966, in the 5th group of astronauts selected. He served as a member of the astronaut support crew for the Apollo 9 flight and as backup command module pilot for the Apollo 12 flight.

Worden served as command module pilot for Apollo 15, July 26 - August 7, 1971. His companions on the flight were David R. Scott, spacecraft commander, and James B. Irwin, lunar module commander. Apollo 15 was the fourth manned lunar landing mission and the first to visit and explore the moon's Hadley Rille and ApennineMountains, which are located on the southeast edge of Mare Imbrium (Sea of Rains). Apollo 15 achievements include: Largest payloads placed in earth and lunar orbits; first scientific instrument module bay flown and operated on an Apollo spacecraft; longest lunar surface stay time (the lunar module, "Falcon," remained on ground for 66 hours and 54 minutes); longest lunar surface EVA (Scott and Irwin logged 18 hours and 35 minutes each during three excursions onto the lunar surface); longest distance traversed on lunar surface; first use of lunar roving vehicle; first use of a lunar surface navigation device (mounted on Rover-1); first sub satellite launched in lunar orbit; and first EVA from a command module out of Earth orbit for which Col. Worden still holds a record for the furthest deep space EVA.

During this EVA Worden logged 38 minutes in extravehicular activity outside the command module, "Endeavour." In completing his three excursions to "Endeavour's" scientific instrument module bay, Worden retrieved film cassettes from the panoramic and mapping cameras and reported his personal observations of the general condition of equipment housed there. Apollo 15 concluded with a Pacific splashdown and subsequent recovery by the USS OKINAWA. In completing his space flight, Worden logged 295 hours and 11 minutes in space. During 1972-1973, Worden was Senior Aerospace Scientist at the NASAAmesResearchCenter, and from 1973 to 1975, he was chief of the Systems Study Division at Ames in California.

After retirement from active duty in 1975, Al Worden became President of Maris Worden Aerospace, Inc., and was Vice-President of BF Goodrich Aerospace Brecksville, Ohio, in addition to other positions within the aerospace and aviation industries.