He has hit three of them in his career. His first being in 1989, his second being in 1994, and his third being last night. I'm wonder how many players have hit a Grand Slam in 3 different decades that they've played in.
Jamie Moyer has played in 3. He hasn't hit 1 grand slam, let alone 3. Has to be the most quiet 20 years in the majors ever.
I also wonder what the record for the most amount of time between grand slams is. Biggio went 13 years between them.
There is actually a discussion about this over at orangewhoopass.com. http://www.orangewhoopass.com/forums/index.php?topic=101755.0 There were a lot more than I thought that had done it. Biggio isn't even the only player to hit only ONE grand slam in 3 different decades.