The Rev. Bonnie J. McCubbin is an only child. Despite that — or perhaps because of it — she found a willing playmate in her grandfather, Albert J. McCubbin.

“The neighbors called us ‘The Bobbsey Twins’ because wherever my grandfather was, I was following him as his little shadow,” Ms. McCubbin said.

Mr. McCubbin, a Baltimore County native who served in two wars and rose to manager within Baltimore Gas and Electric, died Sept. 7 from complications caused by an illness at Keswick Multi-Care Center in Baltimore. He was 100.

Mr. McCubbin was the youngest of two children born to the former Grace O. Miller, a homemaker, and Charles L. McCubbin, a telegrapher for the Pennsylvania Railroad. At the time, the family was living in Bentley Springs in northern Baltimore County.

Four months after his birth, however, Mr. McCubbin lost his father from head injuries suffered in a fall from a horse. More than two years later, his mother bought a house in East Baltimore and turned it into a boarding home.

Until he was 12, Mr. McCubbin split time between his mother’s home in Baltimore and his maternal grandparents’ farms in northern Maryland and southern Pennsylvania.

His son, Bruce J. McCubbin, recalled his father’s perspective on his childhood.

“He didn’t complain about the hand that he was dealt in life, but he did comment about how difficult things were from time to time,” said Mr. McCubbin, who lives in Towson. “I think he felt bad that he couldn’t spend all year with his mother and brother in Baltimore, but had to go with his brother up to — as he put it — ‘the country’ to live with his grandparents. Now at the same time, he loved being with his grandparents.”

Mr. McCubbin enrolled early in the “A” course offered by Baltimore Polytechnic Institute and graduated from high school in 1936 at the age of 16. After graduation, he went to work in the New Business Department of the Consolidated Gas Electric Light Company and Power Company of Baltimore, a predecessor to the Baltimore Gas & Electric Company.

As a file clerk, Mr. McCubbin represented Consolidated in negotiations with residential and commercial property owners to convert the city’s electric system from the old direct current (DC) system to the alternating current (AC) system still in use today.

At the same time, he attended night classes at the Johns Hopkins University, majoring in electrical engineering.

In the latter stages of 1941, Mr. McCubbin shifted to becoming a full-time student at Johns Hopkins and enlisted in the Army Air Corps in the Aviation Cadet program.

After graduating from Johns Hopkins in October 1943 with a bachelor’s degree in electrical engineering, he was promoted to active duty a month later and received aviation training first at Seymour Johnson Field in Goldsboro, North Carolina, and then at Yale University in New Haven, Connecticut.

Discharged as a 1st lieutenant in April 1945, Mr. McCubbin returned to Consolidated as a representative of the Commercial Group within the Industrial Power Department.

During his time in the Army Air Corps, Mr. McCubbin began to court Margaret Ford, who lived two blocks from his mother’s house.

After the war, he had a work social event to attend, and his mother and Ms. Ford’s mother, Minna Margaret Ford, conspired to have the pair go to the event together. That led to their marriage in Baltimore in 1947.

In 1951, Mr. McCubbin was recalled to active duty by the Air Force to serve in the Korean War. During his time at Wright-Patterson Air Force Base in Dayton, Ohio, Mr. McCubbin, now a captain, helped design two ground support power systems for a new Boeing B-47 Stratocruiser long-range bomber.

Discharged once again in 1953, Mr. McCubbin rejoined Consolidated, working with large industrial clients. After Consolidated became BGE in 1955, he served as general supervisor of the industrial section of the industrial and commercial power

Mr. McCubbin continued his rise up the corporate ladder, moving from Industrial Section supervisor to manager of the Residential Sales Department to manager of the Energy Services Department.

After retiring in 1982, Mr. McCubbin worked as a consultant in energy conservation for commercial companies for eight years. He also devoted his attention to caring for his wife, whose health deteriorated after she was diagnosed with rheumatoid arthritis in 1957.

Mr. McCubbin’s treatment of his wife resonated deeply with his granddaughter, who eventually became pastor of Good Shepherd United Methodist Church in Hampden.

“It was from him that I learned the fine art of pastoral care and my ability to care for older congregants and my ability to be an advocate for them when they are sick or are in the hospital or if their families are not involved,” she said from her home in Cockeysville.

“And it’s because of watching my grandfather take care of my grandmother that I became a care provider and wanted to take care of people all the time. That has impacted my career, my family life, my friendships, my everything.”

Funeral services were Sept. 11, with burial at Dulaney Valley Memorial Gardens in Cockeysville.

In addition to his son and granddaughter, Mr. McCubbin is survived by another daughter, the Rev. Ellen M. McCubbin of Hope Mills, North Carolina, and two great-grandsons.