Mount Etna has shown persistent summit activity in recent decades, with the South‑East Crater producing frequent lava fountains and explosive events. A phase of intense paroxysms began in December 2020, preceding two major paroxysmal sequences that lasted until February 2022, with 17 events in the first sequence (February–March 2021) and 33 in the second (concentrated predominantly between May–August 2021). To investigate the processes driving this activity, we analysed ground deformation recorded by Global Navigation Satellite System (GNSS) and Interferometric Synthetic Aperture Radar (InSAR) between January 2020 and February 2022. The pre‑paroxysmal period exhibits a composite deformation field dominated by the eastward acceleration of the eastern flank and accompanied by deep (20–30 km) and intermediate‑depth seismicity that we interpret as evidence of repeated magma injections. Our modelling identifies two distinct pre‑paroxysmal phases marked by upward migration of pressurised sources from ~ 5.5 km to ~ 4.2 km depth. During the paroxysmal sequences, Etna exhibited pronounced centripetal deflation centred on the summit. Sequence 1 produced strong, volcano‑wide deformation driven by rapid magma withdrawal from a shallow reservoir. Sequence 2 showed weaker but more complex deformation, reflecting overlapping contributions from shallow magma input, crystallisation, volatile exsolution and persistent flank slip. The temporal alignment between deep seismicity, compositional shifts towards more primitive magmas and geodetic source migration indicates a vertically stratified and dynamically connected plumbing system. Our results show that Etna’s 2020–2022 paroxysmal cycle was driven by stepwise magma ascent from deep reservoirs to shallow levels, strongly modulated by flank kinematics and evolving storage conditions.