Dale was introduced in the comic strip with no real backstory. She was just a pretty girl sharing an airplane flight with Flash Gordon and got caught up in his adventure. She has no speaking part in the first strip but becomes more active in the second one. When Flash is on the losing side of a skirmish with Dr. Zarkov, Dale picks up a wrench and attacks Zarkov herself.
She fails to stop Zarkov though. She is unconscious for quite a while after that but in the seventh strip Flash proclaimed her to be the girl he loved. At the time he made that proclamation he had only said nine words to her and did not really know her name yet. Their relationship got fleshed out in many stories over the following years.
Flash Gordon Serial (1954)
Jean Rogers plays Dale Arden in both the 13 chapter "Flash Gordon Space Soldiers" cliffhanger serial and in the 15 chapter "Flash Gordon's Trip to Mars" cliffhanger serial. The first serial has Dale Arden with long light blonde hair, while the second serial gives her short light brown hair.
Carol Hughes plays the the role of Dale Arden in the 12 chapter cliffhanger serial "Flash Gordon Conquers the Universe" and interestingly gives us a Dale with short dark brown or even black hair. All three of the Universal Studios Flash Gordon serials are absoutely a cut above most of the cliffhanger serials of the 1930's and 40's. The first Flash Gordon serial has been called the best cliffhanger serial ever made by some serial observers.
Flash Gordon (1980 Movie)
Melody Anderson takes over the role of Dale Arden in the 1980 Flash Gordon movie and she displays short medium brown hair in the film, very close to how Jean Rogers' hair looks in the second serial.
Flash Gordon (2007 Live-Action TV Series)
Gina Holden plays Dale in the 2007-08 SyFy Channel Flash Gordon series and she shows us a Dale with pretty long medium brown hair. The 2007 television version did not show Flash and Dale having a current romantic relationship.