Fast magnetic reconnection is a crucial mechanism for understanding particle acceleration and very high-energy (gamma and neutrino) emission in magnetized systems in general. A potential model to explain the transition between the High/Soft and Low/Hard X-ray states observed in black hole binaries (BHBs) and Active Galactic Nuclei (AGNs) can be attributed to turbulent fast magnetic reconnection events induced in jet/accretion disk systems. According to this model, the power released by such events could accelerate relativistic particles in a first-order Fermi process and produce the observed non-thermal high-energy emission from BHBs and AGNs. In this talk, we will summarize the main insights of our fast magnetic reconnection analytical model and discuss the results of our recent special relativistic magnetohydrodynamic simulations of reconnection driven by kink instabilities inside relativistic jets. We will present a qualitative view of the reconnection structures and a statistical analysis of these events. We have evaluated the magnetic reconnection rates obtaining averaged values comparable with the predictions of the theory of turbulence-induced fast reconnection. Furthermore, preliminary studies of the time-variability of the power released by fast reconnection in our simulations show good agreement with the observations of blazar sources in the GeV band.