Hill was leading a group of nearly 300 USD fans who were at the game to see Bryant, who kept pace with the Rockies' Nolan Arenado in the National League in home runs. Arenado hit his 33rd earlier on Tuesday.
Is Hill surprised at how well Bryant has done in his sophomore season in the big leagues?
"We really stress at USD -- as [Cubs manager] Joe Maddon does -- is don't build a fence around a young person and what they can accomplish," Hill said. "[Bryant] is the same age as my son. When it's your kid and you relate to that, he's just a pup. To be doing all this, really is pretty crazy.
"However, he really is still, at age 24, growing into his body and really becoming strong and really learning to like the strength and conditioning program the Cubs have put in place for him," Hill said. "He's got all of this quick twitch coming his way and it's pretty scary."
Bryant was the Minor League Player of the Year in 2014, and last season he won the NL Rookie of the Year. Hill sees more positives.
"I always thought once he got into pro ball, he'd actually do better than he did in college," Hill said. "In the Minor Leagues, the pitchers get a little arrogant. They think, 'I'll just throw this by this guy.' I thought when he got some pitches to hit, he'd do some damage. They're pitching him like an All-Star and they've been doing it since day one."
Hill also isn't surprised that Bryant has made the adjustments. There's been no sophomore slump.
"He was a 4.7 GPA out of high school," Hill said. "He's very bright, and at the same time, he's very competitive. You have that combination and that's a good recipe for success."
Bryant knew the USD supporters were in the crowd of 33,614 at Petco Park.
"It's pretty cool to hit a home run on the day they're here," he said. "I'm glad they were here showing support."
He also hit a sacrifice fly, drew two walks, and scored another run, and now has hit in six straight games. In his last 15 games, Bryant has seven home runs, 18 RBIs and 20 runs scored.
"I'm just taking advantage of pitches to hit and actually hitting them, and not at people," Bryant said. "The ball is falling for me now."
Hill couldn't stop smiling.
"I'm a proud papa walking around," Hill said.
Carrie Muskat has covered the Cubs since 1987, and for MLB.com since 2001. She writes a blog, Muskat Ramblings. You can follow her on Twitter @CarrieMuskat and listen to her podcast. This story was not subject to the approval of Major League Baseball or its clubs.