It has approximately 90 lawyers and was established in 1939 by Sir Joshua Hassan GBE, KCMG, LVO, GMH, KC.

The firm's current senior partner is James Levy CBE KC, nephew of Sir Joshua.

Former Hassans' partner Fabian Picardo KC is the current Chief Minister of Gibraltar.

Peter Montegriffo: Former MP and Minister for Trade and Industry (1988-1991 & 1996-2000); Current Chairman of the Gibraltar Police Authority (GPA).

[brother of Daniel Feetham] Gemma Arias-Vasquez: Incumbent Minister for Health, Care and Business (since 2023) Hassans also has its own Company and Trust Management corporations, Line Trust Corporation Limited and Line Management Services Limited.