The Oak Crest Village resident was 80.
"He was both my teacher and class adviser, and as a teacher, I loved him. He made a big impact on all of our lives," said Laurie J. Bender, who graduated in 1991 from Parkville High School. "He was one of those teachers who helped you learn in a nonthreatening and humorous manner. Some teachers kept you on edge, but not Joe."
The son of a boxing manager and a homemaker, Joseph Eugene Welsh was born and raised in Baltimore, where he attended St. Elizabeth of Hungary parochial school near Patterson Park.
He graduated in 1951 from Calvert Hall College High School and entered the Christian Brothers. After graduating in 1955 from LaSalle University in Philadelphia, where he earned his bachelor's degree, he embarked on his teaching career.
Mr. Welsh also earned a master's degree in theology, and a master's in U.S. history and political science at Villanova University.
He did additional graduate work at Rensselaer Polytechnic Institute, Hartwick College, Vanderbilt University and Western Maryland College, now McDaniel College.
In 1968, Mr. Welsh left the Christian Brothers and began teaching in the city's Fairmount Hill Junior-Senior High School.
Later that year, Mr. Welsh joined the faculty of Woodlawn High School, where he taught social studies and psychology for 18 years.
In 1986, he began teaching at Parkville High, from which he retired in 1991.
"He always had a smile and put everyone in a good mood," said Ms. Bender, who was a member of Mr. Welsh's social studies class. "He was well-liked by all the students because he was warm and loving. No one disliked him. That would simply be unimaginable."
Ms. Bender recalled when her class held its five-year reunion, Mr. Welsh attended the gathering.
"He brought medals for all of the class officers. It was so sweet," said Ms. Bender, who lives in Carney. "We kept in touch over the years through cards and letters and sometimes we'd go to T.G.I. Friday's."
Ms. Bender said that she reconnected with Phylis Welsh, Mr. Welsh's wife, in 2011 after the couple moved to the Parkville retirement community where she is a senior sales consultant.
As a teaching aide, Mr. Welsh used slides he had taken of historic sites from all over the nation.
"He loved history and he wanted his students to have a sense of history. He had amassed more than 5,000 slides," said the former Phylis Kramer, his wife of 44 years. "That way he kept their attention."
Mrs. Welsh said her husband also had a vast repertoire of jokes that could be used for any occasion.
"He once said to a student, 'If you can't stand for something, then sit,'" she said.
After retiring from county public schools, he continued to substitute-teach at City College.