The main research interest of Sergeev is nonlinear phenomena in physics including plasma physics and physics of femtosecond lasers. Specifically, he guided development of petawatt-class laser in the Institute of Applied Physics RAS.

President of Russian Academy of Sciences (2017-2022)

• Corresponding Member of the Russian Academy of Sciences (2003),
• Member of the Russian Academy of Sciences (2016),
• Foreign Member of the National Academy of Sciences of Belarus (2017),
• Honorary Doctor of Lomonosov Moscow State University (2019),
• Foreign Member of the Chinese Academy of Sciences (2019),
• Honorary Doctor of the National Research Center "Kurchatov Institute"
• Honorary Member of the National Academy of Sciences of the Republic of Armenia (2021)

• Russian Federation State Prize in Science and Technology (1999) for work on optical tomography of biological tissues.
• Order of Honor (2006) for achievements in the field of creating components and devices for high-power laser complexes.
• Russian Federation Government Prize in Science and Technology (2012) for work on creating a petawatt laser complex.
• Gruber Prize in Cosmology (as part of the LIGO collaboration) (2016).
• Officer of the Order of Academic Palms, France (2018).
• Laureate of the international medal "For Contribution to the Development of Nanoscience and Nanotechnology" awarded by UNESCO (2018).
• Order of Merit for the Fatherland, IV degree (September 10, 2020) - for great contribution to the development of science and many years of fruitful work