He completed a Candidate of Sciences in Physics and Mathematics degree (Moscow State University in 1975 under scientific advisor Albert Muchnik.

Semenov conducted his research in the field of mathematical logic, cybernetics, theoretical computer science, artificial intelligence, and education.

Semenov started work in practical computing at age 14 in cooperation with his mother, specifically in speech recognition[16] in the group of Dmitry Pospelov.

[18] The concept furthers the vision of Lev Vygotsky,[19] Josef M. Feigenberg,[20] Sherry Turkle,[21] Andy Clark[22] and Michel Serres[23] to the educational context of mass school.

Alexei Semenov’s theoretical and practical work in education originated in his involvement as a student, and later, as a teacher in the Nikolay Konstantinov’s math schools.

[24] His educational philosophy is rooted in the “learning-by-doing” method of Robert Lee Moore,[25] Paul Halmos,[26] and Russian mathematical circles[24] constructionist approach of Seymour Papert.

[27] Prof. Semenov's approach to learning and teaching math and computer science in primary school is based on Inquiry-based learning, mathematical experimenting by learners, language development, emphasizing visual (on screen and paper) and palpable (manipulatives, moving objects) environments of strings, bags, tables, games, and robots as the basis for all math.

So INT produced Russian adaptations, learning and teaching materials for Logo, educational LEGO, Geometer’s Sketchpad, etc.

[41] Semenov initiated and led in cooperation with Sergey Soprunov the project of Logo-style learning environment for pre-literacy pre-numeracy children, recognized by S. Papert in his book "The Connected Family".

In all school subjects students are introduced to the future by doing its pieces now in such modules like "Introduction" (children to each other, to the teacher, the tablet, and network), "Organization" (keeping myself in time), "Communication" (video-audio-text, as recording the first memory of the eldest in the family), etc.

He is the Director of Axel Berg Institute of Cybernetics and Educational Computing FRC CSC Russian Academy of Sciences (2015 – now).

Grandchildren: Alexandra Semenova – linguist, Ekaterina Possitselsky – molecular biologist, Dmitry, Anastasiya, Grigory, Timothey, Kirill – students, Olga – preschool.