Kalas's Major League debut came during the 1965 season, the first year the team in Houston changed it's name from the Colt .45's and moved into the Astrodome.
The 73-year old Kalas was found unconscious in the Phillies' broadcast booth in Washington D.C. on Monday afternoon at around 12:30 p.m. ET He was rushed to George Washington Hospital, where he was pronounced dead at 1:20 p.m. The Phillies were in Washington for the Nationals' home opener, which Philly won, 9-8.
Kalas joined the Phillies in 1971 and had been a mainstay every since. Before that, he spent five seasons calling Astros games. He was chosen out of over 200 applicants to be a part of the first Astros broadcast team, also serving as the voice for the University of Houston football team and calling the Southwest Conference Basketball Game of the Week for television.
"It's another tragic loss," Astros president of baseball operations Tal Smith said. "You still hear him so much on commercials, and all of those NFL shows. He had a great voice, and he was so knowledgeable. He's certainly one of the greats in the broadcasting annals.
"He was one of four [broadcasting] Hall of Famers who have been with us -- Gene [Elston], Milo [Hamilton], Bob Prince, and Harry."
Hamilton and Kalas went back to their college days. Both were graduates of the University of Iowa, and while they never shared the Astros booth, they obviously crossed paths frequently. On those occasions, Kalas would break out in an Iowa cheer and then say, "Hawkyeye, how ya doing?" Hamilton recounted.
"We'd talk about the Iowa athletic program, then we'd talk about our teams. Compare notes, especially on the first game of a series," Hamilton said. "We had some great visits. When I had my heart attack [two years ago], he was the second person to call me. He called me all during the next month to see how I was.
"He had a distinctive voice and style. He had great ethics, he was a terrific guy. He was very close to the ballclub. He had a lot of friends. What really broke him up was when Richie Ashburn passed away. That was a big loss for him, when Whitey died. And this is a big loss for all of us. He was very popular with the city of Philadelphia."
Astros general manager Ed Wade also has a long history with Kalas. He began his baseball career in 1997 as a public relations intern. Wade left the Phillies for the Astros, then came back in 1989, and he became their GM in 1998.
"It's a very sad thing to have happen," Wade said. "You have over four decades of a guy being the voice of the Phillies. Everyone knew that Harry Kalas and Phillies baseball were intertwined."
"On a personal level, I was a PR intern with the Phillies in 1977," he continued. "He was nothing but kind to me then and he treated me the same way when I was the general manager. It's the kind of person he was.
"He and Richie Ashburn were a team. To have both of them gone, that's a big hit to that organization."
Astros reliever Geoff Geary also came up with the Phillies, in 2003. Wade delivered the news to Geary after the Astros' loss to the Pirates here and the right-hander was visibly shaken. Kalas had reached out to Geary on several occasions, including when he was dealt from the Phillies to the Astros after the 2007 season.
"It's hard to keep myself from crying," Geary said. "When I got traded, He was the first guy to call me in the offseason. He told me it was an honor for him to work with me. He said you always make your way back to where you want to be and that I should take advantage of this to see a different side of the baseball world."
"The first time we came to Philadelphia that year, he came into the clubhouse to find me," he continued. "That shows you want kind of man he was. He was always smiling, always there with open arms.
"He had stories you could spend weeks listening to non-stop. He was a legend and it's sad to hear he's gone. It's another reminder to take every day like it's your last because you never know what's around the next corner."
Jonathan Mayo is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.