Atomic properties of the 24 low-lying ns, np(j), nd(j), nf(j), and ng(j) states in Th IV ion are calculated using the high-precision relativistic all-order method where all single, double, and partial triple excitations of the Dirac-Fock wave functions are included to all orders of perturbation theory. Recommended values are provided for a large number of electric-dipole matrix elements, oscillator strengths, transition rates, and lifetimes. Scalar polarizabilities of the ground and six excited states (5f(j), 6d(j), 7p(j), and 7s), and tensor polarizabilities of the 5f(j), 6d(j), and 7p(3/2) states of Th IV are evaluated. The uncertainties of the recommended values are estimated. These calculations provide recommended values critically evaluated for their accuracy for a number of Th IV atomic properties for use in theoretical modeling as well as planning and analysis of various experiments including development of an ultraprecise nuclear clock and resonant excitation Stark ionization spectroscopy studies of actinide ions.