Trevithick graduated from MIT in electrical engineering and computer science in 1981 and was a research assistant at the MIT Media Lab in 1981 and 1982. In 1981, he co-founded Lightspeed Computers which was ultimately acquired by DuPont. He was CEO and co-founder in 1985 of Archetype, Inc. which became the Pageflex division of Bitstream Inc. in April 1997. He then served as Bitstream's vice president of marketing, and starting in August 1998 its president.
Trevithick has contributed to World Wide Web Consortium, PODI, Organization for the Advancement of Structured Information Standards (OASIS), and ITU-T standards efforts. He was granted the Seybold Industry Vision award in 1999.
From 2003 to 2009, Trevithick worked on open source identity software for Internet security, and privacy for digital identities and social networks on the Internet. He co-authored a paper on "Identity and Resilience" that was one of the 100 papers cited as informing the 2009 US White House CyberPolicy Review.
He initiated and co-led what became the Eclipse Foundation's Higgins project. Supporting this effort, he co-founded SocialPhysics, the IdentityGang (now part of Identity Commons), and Identity Schemas. In 2008 Trevithick founded the Information Card Foundation and served as its chair. In 2009 he co-founded and was a co-chair of the Kantara Initiative Universal Login User Experience Working Group. Trevithick is a past member of the Kantara Leadership Council and a steward of Identity Commons.
In 2009, Trevithick founded Azigo.com a restart of Parity Communications, Inc. and remains its chairman. While at Azigo he designed and led the development of the Experimental Laboratory for Investigating Collaboration, Information-sharing, and Trust (ELICIT) online game  platform under contract to the United States Department of Defense (OASD/NII) Command and Control Research Program (CCRP).
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- Paul Trevithick, William Coleman, John Clippinger and Kim Taipale (April 22, 2009). "Identity and Resilience". Retrieved November 10, 2013.
- "Higgins Team". Higgins website. Retrieved November 10, 2013.
- ULX home page
- "Azigo Team". Company web site promotional biographies. Retrieved November 10, 2013.
- "Experimental Laboratory for Investigating Collaboration, Information-sharing, and Trust". CCRP website. Retrieved November 10, 2013.
- "Command and Control Research Program". CCRP. Retrieved November 10, 2013.
- "Leadership Team". Company web site promotional biographies. PanGenX. Retrieved November 10, 2013.
- White, G. Pawley, A Handbook of Cornish Surnames.