Step 1: Background of Al-Biruni.
Al-Biruni was a great Persian scholar, scientist, and traveler. He was originally from Khwarizm (present-day Uzbekistan region).
Step 2: How he came to India.
When Sultan Mahmud of Ghazni invaded Khwarizm, Al-Biruni was taken as a hostage to Ghazni. Later, he accompanied Mahmud on his Indian campaigns.
Step 3: Conclusion.
Thus, it was Sultan Mahmud who brought Al-Biruni from Khwarizm to Ghazni.
\[
\boxed{\text{Sultan Mahmud}}
\]