Leo James D'Aleo, a Baltimore architect whose lengthy career included designing Mount Vernon's Waxter Center and the Inner Harbor's Scarlett Place, died of congestive heart failure July 10 at his Monkton home. He was 75.

Born in New York and raised in Philadelphia, he was the son of Bernard Francis D'Aleo, an engineer, and Concetta Yolanda Russo.

He earned a bachelor's degree in architecture from North Carolina State University and a master's degree in architecture from Columbia University.

He also studied urban planning at the University of Rome while on a Fulbright scholarship.

He joined the office of Philadelphia architect Vincent Kling, where he learned how to run an architecture studio. He worked with Mr. Kling until 1966, when he was drafted into the Army. He was assigned to Edgewood Arsenal and worked as an architectural manager.

He then moved to Baltimore and joined the firm Tatar & Kelly, where he designed the Waxter Center for Senior Citizens on Cathedral Street. Colleagues noted the dark-brick structure contained curved walls that became Mr. D'Aleo's trademark.

“He had an expressive design talent,” said Walter Schamu, a Baltimore architect. “He was bold in his designs and in his thoughts. He was expansive about what he liked and did not like. He could be outspoken.”

Mr. Schamu recalled that Mr. D'Aleo was an old-school architect who liked to get outdoors to draw and sketch. “He created interesting ins and outs in his buildings suggested by light and shadows in his drawings,” he said.

In 1970, with fellow Tatar & Kelly architect William Meyers, he formed a new firm, Meyers and D'Aleo Architects. The partnership lasted until 1990.

“We rented a broom-closet space in the Mercantile Building,” said Mr. Meyers. “We had room for two persons, and bought a used file cabinet, a hall tree for coats and two drawing tables.

“We eventually grew and had half a floor, then we moved and had 55 people on the 12th floor of the Blaustein Building,” Mr. Meyers said. “We would later have offices in New York City, Myrtle Beach and Ocean City.”

Mr. D'Aleo and his partner received an important commission in the middle 1970s when then-Mayor William Donald Schaefer and then-Housing Commissioner Robert C. Embry Jr. called for a full-scale renovation of Baltimore's City Hall.

A Boston firm headed the design, and Mr. D'Aleo's firm became the local representative of the much-praised City Hall renovation.

He also branched out and began designing large apartment condominiums in Ocean City, including the Golden Sands for Victor Frenkil, owner of Baltimore Contractors. He later designed other Ocean City structures and created a nightclub, Finnigan's Rainbow, with partner John Fager.

In 1985, he formed a sister company, Meyers and D'Aleo Interiors, now known as D'Aleo Interiors Inc.

“He liked rock 'n' roll and he liked opera,” said Martha Ginn Hoelter, a partner in D'Aleo Interiors. “He loved the Rolling Stones, Santana and the Who.”

Mr. D'Aleo also transformed a downtown parking garage, which had been known locally as the “green garage” because of its metal exterior color. Redone, it became the Berkshire Suites Hotel at Calvert and Lombard streets.

He also acquired property along Water Street, at Light Street, and made a cobblestone courtyard surrounded by restored buildings, known as Water Street Mews.

Friends and colleagues said Mr. D'Aleo left his mark on Baltimore. He designed the conversion of an old Pratt Street building, the Scarlett Seed Company, into a luxury condominium on the edge of the area known as Harbor East. He also led a restoration of the Custom House on South Gay Street and a refurbishing of the Lord Baltimore Hotel.

“Leo was an intuitive guy who was creative and was an excellent designer,” said his former partner, Mr. Meyers.

“At Scarlett Place, he wanted to create an Italian piazza to link Little Italy and the Christopher Columbus statue,” said Martha Hoelter, who is the vice president of D'Aleo Interiors.

He also designed an International Longshoremen and Steamship Trade Association building in Dundalk and the Johnston Building at Union Memorial Hospital, where he conceived a tube-shaped walkway that connected a garage and a cancer treatment center.

On University Parkway, facing the Johns Hopkins University, he designed the Colonnade, a condominium, hotel and restaurant.

Other projects included work at the Blakehurst Retirement Community on West Joppa Road in Towson and much of the Green Spring Station campus. He designed two dormitories at Towson University and conducted restorations at Aigburth Vale in Towson and Warren Place in Cockeysville as senior housing.

Mr. D'Aleo also created a cantilevered glass house for businessman Leroy Merritt on the Magothy River.

In addition to painting and sketching, he enjoyed discussing politics. He attended Baltimore Orioles games and was a regular at Opening Day. He was also a Ravens fan.

A private memorial celebration is being planned.

Survivors include his wife, Barbara D'Aleo; two sons, Bernard D'Aleo of Hunt Valley and Leo D'Aleo Jr. of Berlin in Worcester County; two daughters, Andrea Knipfel of Houston and Diana Koska of Phoenix, Baltimore County; and 10 grandchildren. He was formerly married to Katherine Kempf D'Aleo.

jacques.kelly@baltsun.com