Ray Tomlinson was born on April 23, 1941 in Amsterdam, New York. His family shortly relocated to Vail Mills, New York.

As a child, he attended Broadalbin Central School in Broadalbin, New York. He went on to attend Renesselaer Polytechnical Institute in Troy, New York, where he received a bachelor's degree in electrical engineering in 1963. While studying at Renesselaer, he participated in a co-op with IBM.

He pursued post-graduate education at Massachusetts Institute of Technology in Cambridge, Massachusetts, where he received a master's degree in electrical engineering in 1965. While studying at MIT, he worked in the Speech Communication Group, developing a speech synthesizer as part of his master's thesis.

He began work for Bolt, Beranek and Newman in 1967, where he contributed to the development of the TENEX operating system, including the ARPANET Network Control Program and TELNET. While working with ARPANET, he developed an application to transfer files across the network, called CPYNET. Further, he was tasked to write another application, SNDMSG, which sent messages from one user to another on a time-shared system. In 1971, Making use of the concepts of these two tools, he developed a method through which a user of one computer could send a message to a user on another computer.

The first email system, developed by Tomlinson, was done as a "neat idea," and not as a directive by his employer.

In addition to inventing email, he also pioneers using the @ symbol within email addresses, using, as he called it "the only preposition on the keyboard."

While he did not originate the term e-mail, it was in popular usage within ARPANET in the mid 1970s. His preference was for email versus e-mail, as "[he's] simply trying to conserve the world’s supply of hyphens"

He died in his home on March 5, 2016 in Lincoln, Massachusetts at the age of 74 of a heart attack.