Manwaring was born and grew up in Palo Alto, near Stanford University where his father taught.
[4][5] He attended San Francisco Art Institute (SFAI) and studied design with Jim Robertson, of the Robertson Montgomery design firm as well as Gordon Ashby, Barbara Stauffacher Solomon, and Jack Stauffacher.
[1][5] Manwarning designed public signage for a number of cities in the Bay Area during the 1970s through 1990s, often inspired by large scale Supergraphics.
[7] In the 1970s, Manwaring designed an iconic public art sign in the Bayview neighborhood that reads, "India Basin Industrial Park" in Helvetica font, each letter was made of concrete.
[8] In the 1980s, a few San Francisco–based designers were nicknamed “The Michaels” because they all had the same name (Manwaring, alongside Mabry, Cronan, Vanderbyl, Schwab), and later they were known as the "Pacific Wave" according to historian Steven Heller.