  We compute perturbative corrections to $B \to \pi$ form factors from QCD
light-cone sum rules with $B$-meson distribution amplitudes. Applying the
method of regions we demonstrate factorization of the vacuum-to-$B$-meson
correlation function defined with an interpolating current for pion, at
one-loop level, explicitly in the heavy quark limit. The short-distance
functions in the factorization formulae of the correlation function involves
both hard and hard-collinear scales; and these functions can be further
factorized into hard coefficients by integrating out the hard fluctuations and
jet functions encoding the hard-collinear information. Resummation of large
logarithms in the short-distance functions is then achieved via the standard
renormalization-group approach. We further show that structures of the
factorization formulae for $f_{B \pi}^{+}(q^2)$ and $f_{B \pi}^{0}(q^2)$ at
large hadronic recoil from QCD light-cone sum rules match that derived in QCD
factorization. In particular, we perform an exploratory phenomenological
analysis of $B \to \pi$ form factors, paying attention to various sources of
perturbative and systematic uncertainties, and extract $|V_{ub}|=
\left(3.05^{+0.54}_{-0.38} |_{\rm th.} \pm 0.09 |_{\rm exp.}\right) \times
10^{-3}$ with the inverse moment of the $B$-meson distribution amplitude
$\phi_B^{+}(\omega)$ determined by reproducing $f_{B \pi}^{+}(q^2=0)$ obtained
from the light-cone sum rules with $\pi$ distribution amplitudes. Furthermore,
we present the invariant-mass distributions of the lepton pair for $B \to \pi
\ell \nu_{\ell}$ ($\ell= \mu \,, \tau$) in the whole kinematic region. Finally,
we discuss non-valence Fock state contributions to the $B \to \pi$ form factors
$f_{B \pi}^{+}(q^2)$ and $f_{B \pi}^{0}(q^2)$ in brief.
