He was the son of John and Lucy Matricciani. His father, who founded the John Mattricciani construction firm, immigrated from Italy in 1907 and lived in the same house on Exeter Street in Little Italy for the rest of his life.
Father and son worked together in the business. Mr. Mattricciani told family members he began doing his father's payroll work in 1928 when he was in the seventh grade at St. Leo's School.
He was a 1933 graduate of Calvert Hall College High School and served on its building committee when the school relocated from downtown Baltimore to Towson in 1960. He was a 1937 Loyola College graduate and was a standout player who was a guard on its basketball team. A Sun sports reporter called him a "mainstay" of the squad who helped the Greyhounds beat Johns Hopkins 37-25 in 1936. He later studied engineering at Lehigh University.
He officially joined his father's business in the 1930s. During World War II, as a civilian, he worked at the Aberdeen Proving Ground and supervised utility work.
Mr. Mattriciani, who also worked alongside his brother, Albert, undertook the reconstruction of the Druid Hill Lake, a city reservoir, in the 1950s. His crews drained the body of water and installed a new ten-foot-diameter pipe in a tunnel to the Mount Vernon pumping station.
"His strength was the way he gained the respect of his employees," said his son, Guy Matricciani Jr. of Owings Mills. "He made them truly believe they were all a family and they looked out for each other."
In his 70-plus years in the industry, he completed numerous water and sewage projects in Anne Arundel, Howard, Harford and Baltimore counties.
His business also built and repaired numerous water treatment plants in the state and over the years completed projects at the Johns Hopkins University, Loyola University of Maryland, Towson University, Boys' Latin and McDonogh schools.
"Guy and his family were the most progressive utility contractors in Baltimore," said former Mayor Thomas J. D'Alesandro III, a family friend of many years. "He was humble and hard-working and was a stalwart in his field. He helped many poor and immigrant people get jobs."
Mr. D'Alesandro said that Mr. Matricciani was a patriarch of the Italian-American community and was generous to its charities.
"For all of his success, he never asked for any display when he gave. He practiced a non-ego form of charity," said the Rev. Michael J. Roach, pastor of St. Bartholomew's Church in Manchester. "His giving was discreet and broad. People called him Uncle Guy and they knew he would come forward with a check."
Mr. Matricciani was a member of the Associated Italian American Charities, Kiwanis Club of Baltimore, Boystown of Italy, the Little Italy Lodge of the Order of the Sons of Italy and of the St. Gabriel's Society.
He was a past president of the Associated Utility Contractors of Maryland and a founder of the National Utility Contractors Association.
Mr. Matricciani continued to work at his Old North Point Road office until earlier this year.
A Mass of Christian burial will be offered at 10 a.m. Tuesday at St. Leo's Roman Catholic Church, Stiles and Exeter streets, where he was active and was an annual sponsor of the St. Gabriel Festival.
In addition to his son, survivors include two daughters, Mary Jo Vondersmith of Towson and Agatha "Murf" Rosenbaum of Ruxton; 13 grandchildren; and 13 great-grandchildren. His wife of 69 years, the former Agatha M. Corasaniti, died in 2008. A son, John J. "Jay" Matricciani died in 2005. A daughter, Lucy M. Plowden, died in 2009.