On 18 March 1848 he hastened to join those manning the barricades. On 20 March Restelli joined Milan's Committee of Public Security, presided over by Dr.Angelo Fava. A couple of days later Field Marshall Radetsky withdrew the Austrian army from Milan, which left the city under the control of a hastily assembled . On 3 April 1848 Restelli was sent by the provisional government to Venice, which was under the control of its own provisional government, following Radetsky's strategic (and as matters turned out temporary) militarily withdrawal to the "Quadrilatero" forts. Restelli's mission was to foster agreement between Lombardy and Venice, while at the same time promoting the idea of a three way anti-Austrian union that would also include Sardinia-Piedmont.