  The Tile Calorimeter is the hadron calorimeter covering the central region of
the ATLAS experiment at the Large Hadron Collider. Approximately 10000
photomultipliers collect light from scintillating tiles acting as the active
material sandwiched between slabs of steel absorber. This paper gives an
overview of the calorimeter's performance during the years 2008-2012 using
cosmic-ray muon events and proton-proton collision data at centre-of-mass
energies of 7 and 8 TeV with a total integrated luminosity of nearly 30
fb$^{-1}$. The signal reconstruction methods, calibration systems as well as
the detector operation status are presented. The combination of energy
calibration methods and time calibration proved excellent performance,
resulting in good stability of the calorimeter response under varying
conditions during the LHC Run 1. Finally, the Tile Calorimeter response to
isolated muons and hadrons as well as to jets from proton-proton collisions is
presented. The results demonstrate excellent performance in accord with
specifications mentioned in the Technical Design Report.
