There are lots of films where single men act as surrogate fathers, from the John Wayne flick 3 Godfathers to Annie, Curly Sue, Fred Claus, About a Boy, Role Models, Happythankyoumoreplease [yep], Kindergarten Cop, Big Daddy, and (kinda) True Grit. It's also a common trope on TV, in shows where the non-dad "dad" is related to the children in question, like Hangin' With Mr. Cooper, Party of Five, Full House, or Gilmore Girls, and also where a lone man rescues a needy stranger (and himself in the process), as in Punky Brewster.
In the 2005 Disney movie The Pacifier, Vin Diesel plays Shane Wolfe, a Navy Seal–turned–temporary child minder. After failing to protect a government scientist working on a top-secret program that prevents other countries from deploying nuclear weapons, he's sent to protect the man's family as they've experienced some attempted break-ins, presumably in search of the secret program (which Wolfe needs to find before they do). After the scientist's widow leaves for Switzerland to open a newly discovered safety-deposit box belonging to her husband and the hopelessly negligent nanny quits, Wolfe is left in sole control of five children aged from baby to teenager. Hijinks ensue.