Majeed returned to Pakistan in 1974 after India had conducted a surprise nuclear test, codenamed "Pokhran-I". At the Pakistan Institute of Nuclear Science and Technology (PINSTECH) he was assigned to the Nuclear Chemistry Division led by Iqbal Hussain Qureshi. In 1974, Majeed was a part of Munir Ahmad Khans team that had supervised the criticality of the second nuclear pile —PARR-II reactor. After the construction of the third nuclear pile—PARR-III, also known as The New-Labs; Majeed was the first technical director, and was part of a team that supervised the reactors criticality. An expert in plutonium technology, Majeed, as junior scientist, is known for his contribution in the plutonium reprocessing plant and plutonium nuclear fuel cycle technology. Majeed was also a part of a team at the New Labs that had succeeded in attaining fresh supplies of weapons-grade plutonium isotopes, produced by the reactor. In 1990, Majeed was promoted and was made Director-general of Nuclear Chemistry Division (NCD) by Munir Ahmad Khan. Throughout the 1990s, Majeed was responsible for underground work of the nuclear reactor Khushab-I, and the CHASNUPP-I commercial nuclear power plant. There, he was the director of Radiation and Nuclear Safety Division and was omitted from the weapons development teams.
He published extensively in the 1980s and 1990s on nuclear detectors and the use of x-ray diffraction, fluorescence, and crystallography to study a wide variety of materials and elements, including stainless steel, uranium, plutonium, and thorium. Due to his work for the State, he was conferred with the Tamgha-e-Imtiaz awarded by the Prime Minister of Pakistan, Nawaz Sharif, in 1998.