So although Biggio probably has a soft side those close to him are familiar with, most fans and teammates just don't see that part of the veteran second baseman. After all, he and his longtime teammate, Jeff Bagwell, were the poster boys of stoicism on the field. Show no emotion, keep your head down and never, ever crack a smile.
That all changed a bit on Tuesday. Biggio, flanked on either side by his sons, Conor and Cavan, gave a heart-felt, 30-minute press conference to announce his retirement. While he was choked up much of the time, nothing compared to his reaction when he addressed his wife, Patty.
He broke down as he said "God bless you" to Patty, who was sitting in the front row.
Referring to his two sons and his daughter, Quinn, who was still on vacation at the family's home in New Jersey, Biggio said to Patty, "They are you. You raised them. I look in their eyes, and I see you."
If there is a downside to a Major League career, it's the time a player is away from home. When Biggio began his career, he was just two years out of college with few responsibilities outside of baseball.
But as the years progressed, his family grew. Conor Biggio, Craig pointed out, will be driving next year. Cavan is 12 and Quinn is seven.
The Biggios have done everything possible to keep the family unit together over the years. They often accompany Craig on road trips, they attend almost every game and his sons are regular fixtures in the Astros' clubhouse.
But that doesn't mean Craig hasn't been away, a lot. While he understood his responsibilities to his job, he always had a sense of guilt for not being home more. That was very apparent as he addressed his wife during Tuesday's press conference.
"I just want to be a part of your family now," Biggio said. "I want to be there. I can't look [the kids] in the eyes anymore and justify being out of their lives.
"I want to be home. I want to be with you guys. I've done my part, I've done what I'm supposed to do. Thank you. Thank you for raising three great kids."
Patty Biggio was taken aback by her husband's burst of emotion.
"I was surprised," she said. "At home, he's very outgoing and we know how he feels about us. When he'd come in the door, it was always about us, never about him. But to hear him say it publicly, I guess that wasn't what I was expecting him to say today. I was surprised."
Biggio admitted he's become somewhat of a softie as he's gotten older.
"When you're older, your emotions hit you," Biggio said. "I cry all the time now. When I was 20, I never cried. I think it's a maturity, reflectiveness. There's a lot to reflect on and be proud of. When I talk about my kids and my family, it is emotional."
Asked what it's going to be like to have her husband around the house so much, Patty chuckled.
"I'm going to have to get back to you in about six months to let you know," she joked. "I keep asking him, 'Are we supposed to get remarried now? Renew our vows?'
"Like the clubhouse guys were saying to me, he's all mine now. But they're not kidding."
Alyson Footer is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.