Alexander Gegello graduated from the College of Civil Engineers (1920) and from the Academy of Fine Arts, Higher School of Art and Technology (1923). In the 1920s-30s, he was a prominent representative of constructivism.
His major projects included the Traktornaia Street Residential Development, 1927 (together with Grigorii Simonov and A. S. Nikolskii), the Serafimovsky District, the block with a landscape garden (Stachek Avenue, 29-35, 1925-29, in collaboration with the same architects), Gorky House of Culture (4 Stachek Square, 1925-27, in collaboration with Krichevskii). He rebuilt the apartment house, accommodating Vyborgsky House of Culture (15 Komissara Smirnova Street, 1925-29, in collaboration with Krichevskii). He built the complex of Botkin Hospital (3 Mirgorodskaya Street, 1927-30s), the House of technical studies (4 Ivana Chernykh Street, 1930-32), I.I. Gaza House of Culture (72 Stachek Avenue, 1931-35, all were created in collaboration with D.L. Krichevskii). He took part in the construction of the building for the Joint State Political Directorate (OGPU), (4 Liteiny Avenue, 1931-32, see Big House).
He is the author of the monument to V.I. Lenin The Cabin in Razliv (1927), the stele commemorating the shot fire by the cruiser Aurora (Angliiskaya Embankment, 1939). In the second half of 1930s, he turned to the modernization of classical methods, with the free interpretation of ordered forms: Gigant Cinema (44 Kondratyevsky Avenue, 1935-36, in collaboration with Krichevsky), buildings of bath-houses (12 Chkalovsky Avenue, 1 Tchaikovskogo Street, 16 Yaroslavsky Avenue, 1930s) and school buildings (19 Mokhovaya Street, 1935; 24 Robespierre Embankment, 1936-50), apartment houses (206-208 Moskovsky Avenue, 1937-40, in collaboration with V. S. Vasilkovsky). He reconstructed the ensemble of Anichkov Palace in the Palace of Pioneers (1936-37, in collaboration with Krichevskii) and the airport building (Pulkovo-2, 1948-51, together with other architects).He taught at the Politechnical Institute (1920-24) and at Leningrad Institute of Municipal Engineering (1928-33). He was a head of the administration of Leningrad Union of Architects (1937-48). As of 1950, he worked in Moscow as Vice President of the Academy of Architecture of the USSR (from 1950). He undertook theoretical research issues in architecture. He is the author of the book Of My Artistic Experience (L., 1962).