Al-Mashaan founded the ALARGAN International Real Estate Company in 1994. It operates in Kuwait, Saudi Arabia, Bahrain, Oman and Morocco with a portfolio including ARGAN Albida’a Hotel & Resort, ARGAN Business Park, Movenpick Albida'a Hotel, ARGAN Riaya Hospital, ARGAN Bedaya Community Center, ARGAN Catering, Telal Al Qurm Integrated Touristic Complex, Al Bustan Residences and SARAY. In the first nine months of 2024, the company had total assets of $847.4 million and recorded gross profits of $6.9 million.Al-Mashaan is also the chairman and board member of a number of NGOs including Kuwait Green Building Council and Kuwait Hotels Owners Association.