The total number of heroes in Overwatch 1 after all of its updates was 32. The original game launched in May 2016 with 21 playable heroes, and Blizzard expanded that roster through free post-release updates.
The additions included well-known heroes such as Ana, Sombra, Orisa, Doomfist, Moira, Brigitte, Wrecking Ball, Ashe, Baptiste, Sigma, and Echo. Echo was introduced in April 2020 and became the 32nd hero in the original Overwatch roster. Blizzard then shifted its development focus toward Overwatch 2 rather than adding another hero to the first game.
A common source of confusion is mixing the original launch roster with the final Overwatch 1 roster. The game began with 21 heroes, but that was not the lifetime total. It is also easy to count Overwatch 2 heroes alongside the original cast, especially because Overwatch 2 initially inherited the original roster. For the historical Overwatch 1 roster at its final update, however, 32 is the canonical count.