Maris began his career as a biotechnology and healthcare portfolio manager for Swedish investment firm Investor AB.

[citation needed] In the mid-2000s, Maris partnered with entrepreneur David Green to transfer a novel hydrophobic acrylic lens to Aurolab to cure cataract blindness in the developing world, where it has been used in more than 30 million patients.

[citation needed] While at GV, Bill managed $2.5B and made 400+ investments in companies including Nest, Uber, Flatiron Health, Robinhood, Cloudera, Carbon 3D, Slack, Duo, The Climate Corporation, Impossible Foods, Aurora, Jet, and 23andme.

[17][18][19][20][21] Maris founded Calico, a multibillion-dollar company whose mission is to understand and influence the genetic basis of aging.

[22][23][24] In a 2015 interview, Maris stated that health care breakthroughs can significantly improve the quality and duration of human lifespan across the globe, and that he is looking to invest in promising biotechnology companies.