In the winter of 1951, at the age of 16, Sternhell immigrated to Israel under the auspices of Youth Aliyah, and was sent to Magdiel boarding school. In the 1950s, he served as a platoon commander in the Golani infantry brigade, including the Sinai War. He fought as a reservist in the Six-Day War, the Yom Kippur War and the 1982 Lebanon War. and defined himself in 2008 as still a 'super-Zionist'.