Despite succeeding Star Trek: The Next Generation's Admiral Jean-Luc Picard (Patrick Stewart) as Captain of the USS Enterprise-E, Captain Worf (Michael Dorn) got his most valuable command experience during Star Trek: Deep Space Nine. As DS9's Strategic Operations Officer, Worf served as Executive Officer to Captain Benjamin Sisko (Avery Brooks) aboard the USS Defiant. Worf learned his first valuable lesson about command during the lead-up to DS9's Dominion War, when he exacerbated an already tense political situation between the Federation and the Klingon Empire.
Despite this initial hurdle, Worf led the USS Defiant into many battles during the Dominion War, and proved himself to be an excellent Starfleet Captain. However, at some point after both Star Trek: Deep Space Nine and the final TNG movie Star Trek: Nemesis, Worf had a command catastrophe. Details on the disaster that befell the USS Enterprise-E are classified by Starfleet Command, but Worf asserts that the incident wasn't his fault. The fact that he retained his Captain's pips suggest that Starfleet Command agreed with the Klingon's assessment or consulted his near-exemplary command record from DS9's Defiant.
