In 1999, with Ireland-based real estate entrepreneur Brian Moran, he created his first company, a construction collaboration technology business called BuildOnline, where he also served as chief executive officer.^[4] BuildOnline merged with US-based rival Citadon in December 2006.^[5]

By September 2006, Suster had already left Citadon, having established a second company called Koral, a content collaboration software business.^[6] In April 2007, Koral was acquired by Salesforce.com where Suster then assumed the role of Vice President of Product Management upon the completion of the acquisition.^[7]

Suster later joined Upfront Ventures (previously known as GRP Partners), a venture capital and investment firm, in 2007.^[8] In 2009, Suster started the Launchpad LA accelerator while continuing his employment at Upfront.^[9] At Upfront, Suster led investments in companies including Ring, Bird, Invoca, ThreadUp, MakeSpace, mitu, Nanit,^[10] Osmo, Tact, and uBeam.^[11]

Suster also led the initial funding round for, and was on the board of, Maker Studios, an online video talent agency (acquired by Disney in 2014).^[12] He was also an early investor in online car-shopping system TrueCar, which went public that same year.^[13] Unlike other Silicon Valley technology entrepreneurs, Suster has been open about turning down investments in potential start-up businesses that later became successful, including Uber.^[14]

In February 2023, Suster said an excess of capital in the startup market was keeping many startups afloat. Of 5,000 early-stage companies Upfront Ventures had funded since 2019, half were at risk of going out of business, he said.^[15] Less than a month later (11 March 2023), Suster called for calm as investors became concerned about the collapse of Silicon Valley Bank, suggesting a "handful" of VCs were creating panic.^[16]

Suster and Upfront are hosts of the Upfront Summit, an invite-only VC conference in Los Angeles.^[17] The event brings more than 1,000 attendees each year and have taken place in locations such as Paramount Studios, the Rose Bowl, and Dolby Theatre. ^[18]

Investors including Upfront Ventures/Suster have been in lawsuits brought by Loot Crate^[19] and Maker Studios.^[20]

Suster grew up in Northern California and is a dual citizen of both the United Kingdom and the United States. He is of Romanian Jewish ancestry.^[21] Suster graduated from the University of California, San Diego with a Bachelor of Arts in Economics. He later received his MBA from the University of Chicago's Booth School of Business.^[22]

Since he was diagnosed with ADHD in 2014, Suster has openly talked and written often about how he's learned to integrate his business skills with his coping strategies for ADHD.^[23]

Suster is married with two children.^[24]