She is also the co-founder and former Chief Executive Officer of Single Stop USA, a nonprofit that promotes economic mobility by connecting people to untapped US Government benefits.

[3][4] Prior to co-founding Single Stop USA, Mason was a Managing Director at the Robin Hood Foundation and practiced law at Cleary, Gottlieb, Steen & Hamilton in New York.

[13] Mason has served as an advisor to the United Nations and to local and international agencies on various human and children’s rights, legislative reform, juvenile justice, and community and youth development programs.

[17] In February 2019, Mason was featured in a World Bank special session broadcast live in 180 countries on the emerging issues in Digital Technologies and Inclusive Development.

She has been said to have links to global legal financing firms like Therium and Silicon Valley tech giants like Facebook, both of which are said to have interests in the oil-rich Sabah region.

[19] Separately, a Euronews report said, “Elisabeth Mason, another lawyer representing the Sulu heirs, works closely with executives from tech giants Google and Facebook.

Famously, both have been accused of backing organizations involved in climate denial and making millions from ads for ExxonMobil, BP, Chevron and Shell or entities like The American Petroleum Institute.”[20] In April 2023 Maurizio Geri wrote in Real Clear Defence that “there can be little doubt then that as long as Malaysia refuses to budge on exemptions for foreign vessels operating in Sabah and continues to move in a pro-China direction on digital infrastructure, major American tech firms may well have an underlying interest in undermining federal control over Sabah”.

[21] Geri wrote that Mason’s close proximity to “US tech giants raises the question of whether the lawsuit representing the Sulu heirs is linked to interests with a much larger stake in the geopolitical rivalry unfolding in the Asia-Pacific over control of the region’s data networks”.

[21] Mason - and Paul Cohen of the British law firm 4-5 Gray's Inn Square – was the lead co-counsel for claimants in the high-profile Malaysia-Sulu arbitration case.

He was sentenced to six months in prison and banned from acting as an arbitrator for one year for “knowingly disobeying rulings and orders from the Madrid High Court of Justice”.