Born in Philadelphia, he graduated from South Philadelphia High School and from Kings Point U.S. Merchant Marine Academy in 1951. He earned a master mariner's license and served as a Merchant Marine officer before earning a degree at Temple University School of Law. He was admitted to the Pennsylvania Bar in 1962.
He formed an initial partnership with two of his brothers, Faustino and John, in 1965. Later, he hired brothers Blasco and Eugene.
Mr. Mattioni was an accomplished trial lawyer. At various times, he served as a Philadelphia assistant district attorney and a Pennsylvania deputy attorney general. He served at the Pennsylvania Constitutional Convention in 1967 and 1968 and was a member of the board of the Philadelphia Housing Authority.
As a result of his generosity and dedication to others, Mr. Mattioni was named a Cavalier of the Republic of Italy and a Man of the Year by the Maritime Society of Philadelphia.
He was chairman of the Chapel of Four Chaplains, and served on the boards of the Philadelphia Historical Society of the U.S. District Court for the Eastern District of Pennsylvania, the Maritime Exchange for the Delaware River and Bay, and the Ports of Philadelphia Maritime Society.
Joe Curran knew Mr. Mattioni for six years when Curran was CEO and Mr. Mattioni a board member at the Malvern Institute, which treats those with addictions. He described Mr. Mattioni as bright, knowledgeable in many areas, and driven to help others as a volunteer.
"What Dante brought to the board was a sense of intense caring and compassion for the individual [seeking treatment]," Curran said. "But he felt that individuals had a responsibility to participate in their own recovery."
Surviving are his wife, Susan; a daughter, Jennifer; five sisters; and two brothers. Two brothers died earlier.
A visitation starting at 10:30 a.m. Saturday, May 10, will be followed by an 11 a.m. memorial service at St. Paul's Episcopal Church, 22 E. Chestnut Hill Ave., Philadelphia.
Donations may be made to the Wounded Warrior Project, www.woundedwarriorproject.org.