Leo I. Welsh, who owned an advertising specialties business and was a stalwart presence in Baltimore Irish American organizations, died June 22 at the University of Maryland St. Joseph Medical Center.

His son, Christopher Welsh, said his father was found unresponsive in the hospital’s waiting area. Mr. Welsh had taken his wife to the hospital and suffered an apparent heart attack.

He was 81 and a lifelong Mount Washington resident.

Born in Baltimore and raised on Appleby Avenue, he was the son of Edmund Welsh, a Rice’s Bakery salesman, and Delia Donahue, a homemaker.

He attended the Shrine of the Sacred Heart School and was a 1960 graduate of Calvert Hall College High School, where he played baseball and football.

A skilled dancer with an outgoing personality, he established a circle of friends and often danced with his dates at the old Mount Saint Agnes High School and the Alcazar Ballroom.

He attended the University of Baltimore and served in the Coast Guard Reserves.

While a high school senior, Mr. Welsh started working for Dave Rosenberg of David’s Jewelers in downtown Baltimore. The apprenticeship led to a career in sales and promotions. The business was later renamed Tri-State Distributors, Inc.

Mr. Welsh rose to become its president and purchased the firm, which expanded to sell promotional advertising items, including keychains and T-shirts imprinted with businesses’ names.

He moved the business to North Avenue and Howard Street and later to Lauraville before closing it in 2018..

He met his future wife, Susan Giblin Welsh, on a blind date arranged by a colleague. They married in 1969.

Mr. Welsh joined the Ancient Order of Hibernians St. Brendan’s Division #3 in Towson. He also visited Ireland and met his mother’s cousins in Galway.

“My father was an extrovert and a people person,” said his son, Christopher. “He was known as Uncle Leo and for good reason. He had an institutional memory, and he had something to say.”

He served as Maryland State AOH president several times and was the co-chair of its 2000 Baltimore national convention.

Mr. Welsh became involved with the Maryland Irish Festival and the Baltimore St. Patrick’s Parade. He was a co-founder and past president of the Irish Charities of Maryland and of St. Patrick Celebrations Inc., the group that stages the annual parade along Charles and Pratt streets.

Mr. Welsh also organized a booth promoting the pubs that supported the Irish festival. The booth was stocked with Irish-themed glassware and T-shirts.

After marching in the annual parade for many years and being its 1992 grand marshal, Mr. Welsh decided he preferred to stand at Charles and Pratt streets.

“He had a clipboard and eyeballed the units. If any had dropped out or was out of order, he relayed [the information] on a walkie-talkie to the reviewing stand so the names of the marching units could be correctly announced,” his son said.

“Leo was easygoing and did things in his low-key, unassuming way,” Tim Harvey, a friend, said. “His work was never for recognition, and he sought the good of the cause.”

Mr. Welsh kept up his Calvert Hall ties through its alumni association and was the 1997-98 president of the organization.

“Leo was in the last class to graduate from the old Hall, [in downtown Baltimore] at Cathedral and Mulberry streets. His class remained very active and was a large presence at the annual homecoming,” Art Casserly, another friend, said. “He was incredibly likable. He had no pretense. He worked hard and took credit for nothing. He always treated people like an old friend.”

In 1987, Mr. Welsh joined the Catholic War Veterans and was the Commander of the Msgr. Hugh J. Monaghan Post 736. He also belonged to the Towson Elks Lodge 469.

A funeral Mass will be held at 11 a.m. Sept. 16 at the Shrine of the Sacred Heart Roman Catholic Church at 5800 Smith Ave., where he was a past parish council president and Eucharistic minister.

Survivors include his wife of nearly 53 years, Susan Giblin Welsh, a retired Roland Park Country School nurse and secretary; a son, Christopher David Welsh of Baltimore; a brother, James Welsh of Catonsville; and three grandchildren.