Former University of Montana President George Dennison died Tuesday from complications of non-Hodgkins lymphoma, according to UM.

Dennison, who grew up in the Flathead Valley, was the longest-serving UM president. He was 81.

He retired in 2010 after leading the university for 20 years.

“George was not only our longest-serving president, he was among our finest,” UM interim-President Sheila Stearns said in a press release Tuesday afternoon. “With his expansive vision, tenacity and optimism, he seemed to think the University of Montana could take over the world. That confidence was always half-scary and completely contagious. The University of Montana has lost a wonderful champion, and I’ve lost a dear friend.”

Dennison had been battling cancer and passed away Tuesday morning at St. Patrick Hospital in Missoula, surrounded by family. His family is planning a celebration of life in May, and details will be shared as they become available, according to UM.

“He was an exceptional leader,” said George Ostrom, a longtime Flathead radio personality and newspaper columnist. “He brought great progress to UM. The university made great strides under his leadership.”

Former Montana Secretary of State Bob Brown of Whitefish called Dennison “a truly great man.

“He was probably the greatest president UM has ever had,” Brown said. “He was always a fighter for the University of Montana and many other good causes. He was a proud and happy warrior, and as true and good a friend as one could have.”

Brown said he and Dennison shared a love of history and served together on the Montana Historical Society board of trustees. Brown also worked for UM for close to 10 years and furthered his friendship with Dennison during that time.

Dennison’s tenure as UM president was a time of sustained growth and accomplishment. Student enrollment increased nearly 50 percent, from 10,055 in 1990 to nearly 15,000 in 2009, UM said. The University also added 1.3 million square feet — about 20 percent more total space — while he was president. He helped to establish the Davidson Honors College at UM, and built a culture of philanthropy among UM alumni and friends, increasing the campus endowment from $17.3 million to $120 million. He completed two fundraising campaigns for buildings, scholarships and other needs.

“He was very personable and very smart,” said Ostrom, who served on the UM President’s Citizen Advisory Council during Dennison’s tenure. He and Dennison also grew up together as “miners’ kids” because both of their fathers worked at the Flathead mine near Kila.

Dennison, a 1953 graduate of Flathead County High School, excelled in both academics and athletics. He played tackle for the Flathead Braves his senior year under legendary coach Frank Little, according to Daily Inter Lake archives. Dennison enlisted in the U.S. Navy following high school.

An April 1962 Inter Lake article titled “Dennison is Top student” notes how Dennison, the son of Mr. and Mrs. Earl Dennison of Kila, was featured in an issue of the Montana Kaimin, the student newspaper of UM, then called Montana State University.

“The Kaimin reported Dennison’s grade average to be straight As — and he is married and holds two jobs,” the Inter Lake reported. Dennison was a college senior at the time, and earned a Bachelor of Arts degree in history, with highest honors, in 1962. A master’s degree in history followed in 1963, and he earned his doctorate in history from the University of Washington in 1967.

Prior to becoming UM president, Dennison taught history and served in administrative positions at Western Michigan University, Colorado State University, the University of Washington and the University of Arkansas.

Dennison received many awards and honors during his career, and his extensive curriculum vitae mentions scores of presentations, research reports, publications and special administrative assignments, UM said. In 2007 he received a Montana Excellence in Leadership Award.

He recently had completed his second book, “Montana’s Pioneer Naturalist: Morton J. Elrod,” which was published in September 2016 by the University of Oklahoma Press. Elrod School in Kalispell is named after Morton J. Elrod.

Dennison’s first book, “The Dorr War: Republicanism on Trial, 1831-1861,” also reflected his love of history.

Brown, who spoke at Dennison’s retirement party in 2010, said he’ll remember his good friend’s spontaneous smile and gestures, as well as his charisma.

“He had a presence that was powerful, but not threatening,” Brown commented. “He was a no-nonsense leader, a take-charge guy but in a positive way, and he was inspirational. ... I had enormous respect for him.”

Features editor Lynnette Hintze may be reached at 758-4421 or at lhintze@dailyinterlake.com.