Since the mission of Tore Supra is to produce quasi-steady-state discharges, the lower hybrid current drive (LHCD) system constitutes the most important method of additional heating and noninductive current drive. A description of the LHCD system is given, including the different launcher designs developed for the Tore Supra long-pulse program. Following the completion of the Composants Internes et Limiteur project, together with the installation of a high-performance LHCD launcher, world record discharges, injected and extracted energy exceeding 1 GJ, were obtained in 2003. With the flexibility of lower hybrid (LH) waves to tailor the current profile, an enhanced performance regime, the so-called LHEP, has been maintained in quasi-steady-state discharges. Detailed measurements of the fast electron distribution have allowed us to constrain LHCD ray-tracing models and to quantify parametric dependencies describing the fast electron tail. Localized heat loads on the LHCD launchers due to interaction with fast particles have been measured and quantified, using infrared imaging and calorimetric measurements on water-cooled plasma facing components. Furthermore, experimental results in the area of LH wave coupling are presented.