Keegan peaked in 2007 and holds at current rank #594, with 38,063 total SSA bearers. It's an Irish surname that crossed into American first-name use in the 1990s and 2000s — part of the same Celtic wave that brought Brennan, Callahan, and Finnegan into broader American use. Keegan has a specific energy: sporty, Irish, and slightly more original than Connor or Liam.
Son of the Fiery One
Keegan is an Anglicization of the Irish Mac Aodhagáin, a patronymic meaning "son of Aodhagán" — a diminutive of Aodh, the old Irish god of fire. Aodh gives us Hugh in English, and Keegan is thus a distant relative of Hugh via a completely different linguistic route. Fire gods and warrior associations are the deep Irish etymology; by the time the name reached American nurseries, all of that had compressed into a friendly two-syllable sound. The fire heritage is there for parents who want it.
Keegan-Michael Key and the Name's Pop
Keegan-Michael Key — the comedian and actor known from Key & Peele and dozens of film and television appearances — is the most visible contemporary bearer of this name. His career arc from sketch comedy to mainstream Hollywood has given Keegan a smart, funny cultural association that reinforces the name's appeal for parents who want something Irish-origin without going full traditional.
The 2007 Peak and the Road Back
Like many Irish-surname names that peaked in the mid-2000s, Keegan now carries a gentle late-aughts vintage. The question is how quickly it cycles back : Irish names tend to have longer revival periods because the heritage pull keeps them from becoming purely dated. Parents who want the Celtic energy right now might find Keegan feels slightly used; parents willing to ride a gentle recovery cycle might find it's ready for reconsideration. Compare it with Cormac or Ronan for Irish-origin names at different points in their trajectories.