He was a rector of the Belarusian State University (BSU) from 1996 to 2003 and a government minister serving under Belarus President Lukashenko but later fell out of favor.

In 1976 he continued his studies at the Faculty of Mechanics and Mathematics of Belarusian State University, he graduated with honours in 1983.

[3][4] Several weeks before the 2006 presidential election, on 2 March 2006, Kazulin was beaten and detained by police after attempting to enter the All Belarusian People's Assembly.

Witnesses testified that police fired into the air to stop a car carrying journalists and members of Kazulin's election team.

Reportedly he walked to the commanding officer with flowers in his hand, and police knocked him off his feet, beat him up, and then detained him.

[13] On 26 February 2008, he was allowed to attend his wife's funeral, after threatening to go on hunger strike[14] and with significant pressure from EU and US officials onto Belarusian government.

As David Kramer openly stated, the reason was "the unwillingness of the Belarusian government to release Alexander Kozulin".