Called the "unsung son," Mr. Modell was considered an architect of the Ravens team that won Super Bowl XXXV in 2001.
"Much of what the Ravens are today can be traced to David and what he directed and established," team owner Steve Bisciotti said in a statement. "Above all, he was a sweet, kind man who helped me when I was first involved. I smile remembering what we shared and what my friend David offered."
Ravens coach John Harbaugh said, "David reached out to us and was so welcoming, accepting and encouraging. We became good friends, and I loved his enthusiasm, his spirit, his depth and his humor.
"His superstitions helped, too," Mr. Harbaugh said. "We had a secret handshake and hug every Thursday in our weight room during our Super Bowl season."
"David hated losing," recalled Baltimore Sun columnist Mike Preston. "And when he won that [Super Bowl] trophy — he called it Silver Betty — he slept with it. He never cleaned it. He wanted people to touch it and he took it everywhere."
David Modell was born David Orrick McDearmon Jr. in Los Angeles.
His parents were involved in television. His mother, Patricia Breslin Modell, was a regular character on 1950s and '60s television shows, including "The People's Choice" and "Peyton Place." His father, David Orrick McDearmon Jr., directed episodes of the television shows "Peter Gunn," "The Twilight Zone" and "Bewitched." They later divorced.
Art Modell, a Cleveland advertising executive who owned the Cleveland Browns, adopted him in 1969 after his marriage to Ms. Breslin. The 9-year-old became David Modell and bonded enthusiastically with his adoptive father, family members said.
He was a graduate of the Gunnery School in Washington, Conn., and attended Wittenberg University.
At age 14, he started working as a Cleveland Municipal Stadium grounds crew member. He also accompanied his father with the team on road trips.
After Art Modell moved the National Football League franchise to Baltimore, the younger Mr. Modell worked with the selection of the Ravens' team colors, its logo and the design of its uniforms. He also launched a campaign to hire a head coach and supervised the opening of what is now M&T Bank Stadium in 1998.
"His fingerprints are still present on many of what have become Ravens favorites and traditions," the Ravens organization said in a statement.
In 1999, Art Modell announced that his son would become the team's president and chief operating officer.
"This is a dream day for me," David Modell said in a Sun article at the time. "I love to work, and I love to go to work with these great associates at the Ravens. I love this organization, and the love will grow as we share future victories. To become president of this organization is humbling."
His father told The Sun at the time: "We're a family business, and this is the logical next step. Oftentimes, family members do not get enough credit for working hard and having talent."
"I first met David when I was with the [Minnesota] Vikings and we were playing the Ravens," recalled former Ravens head coach Brian Billick. "After that game, David approached me on the field and introduced himself to me. He looked around the stadium and said, 'I always knew you would look good in purple,' a reference to the Viking colors — and to Baltimore's.
"He went on to lead the group that ultimately hired me," Mr. Billick said.
"He talked about a Super Bowl championship since Day One, back in the days when it appeared to be far-fetched," said Mr. Preston in a 1999 column. The column said Mr. Modell "can be loud and use big words. He often puffs on big cigars. He is seen on the sidelines wearing designer suits and chewing tobacco, and is often bent over with his hands on his knees as if he is a wannabe coach or just enjoying his toy.
"The main thing that comes to mind was just how approachable he was," said former Ravens wide receiver Qadry Ismail. "As a player, you hear about owners and their families and how they can be a little distant, but he just had such an easygoing way about him that I always enjoyed."
"His father was like a father to me, and David was like a brother," said former Ravens linebacker Ray Lewis. "He had a way of making everyone around him feel special, which was such a gift. I feel truly blessed to have known him, and I will miss my brother greatly."
Mr. Modell led Modell Ventures and was chairman of 3ality Digital, a 3-D entertainment venture.
He was also executive producer for "U2 3D" a concert movie that showcased the band U2's performances through South America and Australia during the 2006 Vertigo Tour. He also worked in radio and appeared with radio host Armstrong Williams.
Mr. Modell sat on the boards of the United Way of Central Maryland; the Port Discovery Children's Museum; Father Martin's Ashley, now Ashley Addiction Treatment; the University of Maryland Medical System Shock Trauma Center; and the Maryland Public Television Foundation.
He was also the chairman of the Ravens Foundation for Families, according to a resume prepared by the Ravens organization. He received the 2002 Ed Block Courage Award.
While in Cleveland, Mr. Modell served as president of the Diabetes Association of Greater Cleveland. He sat on the board of the Cleveland Urban League and the Convention and Visitors Bureau. He was also involved with the Lake County Boy Scouts Association and served on Case Western Reserve University's athletic department's visiting committee.
Information about funeral services was not immediately available.
Mr. Modell is survived by his wife, Michel, an artist; three sons, Arthur Modell, David Modell Jr. and Bertram "Bertie" Modell; three daughters, Breslin Modell, Collier Modell and Aoife "Fee" Modell; and a brother, John Modell of Los Angeles. A previous marriage ended in divorce.
His mother died in 2011. Art Modell died in 2012.