A notable achievement was his discovery in 1960 of the Suzuki groups, an infinite family of the only non-abelian simple groups whose order is not divisible by 3. The smallest, of order 29120, was the first simple group of order less than 1 million to be discovered since Dickson's list of 1900.
He classified several classes of simple groups of small rank, including the CIT-groups and C-groups and CA-groups.
Suzuki, Michio (1969), "A simple group of order 448,345,497,600", in Brauer, R.; Sah, Chih-han (eds.), Theory of Finite Groups (Symposium, Harvard Univ., Cambridge, Mass., 1968), Benjamin, New York, pp. 113–119, MR0241527
Suzuki, Michio (1982) [1977], Group theory. I, Grundlehren der Mathematischen Wissenschaften [Fundamental Principles of Mathematical Sciences], vol. 247, Berlin, New York: Springer-Verlag, ISBN978-3-540-10915-0, MR0648772
Suzuki, Michio (1986) [1978], Group theory. II, Grundlehren der Mathematischen Wissenschaften [Fundamental Principles of Mathematical Sciences], vol. 248, Berlin, New York: Springer-Verlag, ISBN978-0-387-10916-9, MR0501682[1]
[1] M. Aschbacher, H. Bender, W. Feit, R. Solomon, Michio Suzuki (1926–1998), Notices Amer. Math. Soc. 46 (1999), no. 5, 543–551.
Harada, Koichiro (2001), "Michio Suzuki"(PDF), Groups and combinatorics—in memory of Michio Suzuki, Adv. Stud. Pure Math., vol. 32, Tokyo: Math. Soc. Japan, pp. 1–39, MR1893490