"A nice man and a class guy," said former Reds general manager Wayne Krivsky, now a special assistant with the Twins, who got his first job in baseball working for O'Brien with the Rangers in 1977. "For me, Dan O'Brien Sr. will always be a special person in my life.
"He was the first baseball man I worked for. He was a really good person who had a good sense of humor and a dry wit. He always had time to talk to you. He was a mentor. It's very sad to hear about his passing. I always have fond thoughts of him."
Outwardly genial and easy-going, O'Brien occasionally found his equanimity tested while working for hands-on owners like Brad Corbett in Texas and George Argyros in Seattle.
"He had the personality to survive," noted MLB.com columnist Tracy Ringolsby, a beat writer when O'Brien was with the Mariners. "Nothing bothered him as long as he could have a dish of ice cream to cap off the night."
O'Brien also could be tough when he needed to be. While he was an assistant general manager with the Indians, he found himself in a bitter contract dispute with up-and-coming slugger Joe Carter. "What Joe has to realize is that he's going to make millions of dollars in this game. He's just not going to make them all this year," the executive said, holding his ground.
Or, as his biography in the 1977 Rangers media guide noted: "[He] has impressed observers with his wit, knowledge and sensible approach to sometimes complex problems. A smile is Dan's umbrella and he generally can send his staff, fans and player personnel on their way feeling better following a chat. When he comes to a conclusion after exhaustive study of a subject, however, he can be the steely sort."
While he was with the Rangers, the team traded for two Hall of Fame pitchers: Gaylord Perry in '75 and Bert Blyleven in '76.
O'Brien attended Seton Hall University and graduated from Florida Southern. After one year of being responsible for the baseball operations of the Burlington-Graham Pirates, he worked as general manager of the Boise Braves (1956-58), Jacksonville Braves ('59), Louisville Colonels (1960-62) and Greenville Braves ('63).
After spending 10 years with the National Association, he joined the Rangers as a vice president in '73 and was soon promoted to general manager. He remained in that position through '78, although he shared power with Eddie Robinson the last two years.
In '79, he became president of the expansion Mariners, then in their third year of existence. Two years later, he replaced Lou Gorman, adding the GM title to his duties. He left the Mariners in '84 and joined the Indians' front office in '86, spending most of that time as the top assistant to Hank Peters.
After the '89 season, O'Brien moved to the Angels and became a special assistant to Mike Port. He then succeeded Port from the end of the '91 season through '93. After leaving the Angels, he worked in the baseball operations department of the Arizona Fall League from 1994-96, then served as executive director of USA Baseball from '97 through his retirement in 2000.
He is survived by his wife, Mary Ann; his son, Dan Jr.; and daughter, Lori. Dan Jr. has been general manager of the Reds, farm and scouting director of the Astros, assistant general manager of the Rangers and special assistant for the Brewers.
Funeral arrangements are pending.