His first published work was as a trainee illustrator in the art department at D.C. Thompson, inking the black squares in the weekly Sunday Post crossword.
He worked at Amalgamated Press's Knockout from 1953 and worked as a freelance artist for D.C. Thompson again from 1955.
In the 1950s he mainly illustrated war comics, but switched to science fiction in the 1970s.
Kennedy mainly works in acrylic paint when producing cover art, including those for the annual RAF Leuchars Air Show's programmes.
Kennedy went into semi-retirement in 1997 but has drawn covers and features for Commando from 2012.
- M.A.C.H. 1: Vulcan (with Robert Flynn, in 2000AD Prog 2, 1977)
- Tharg's Future Shocks: The Collector (with Kelvin Gosnell, in 2000 AD Prog 210, 1981)
- Judge Dredd: 99 Red (with John Wagner/Alan Grant, in 2000 AD Prog 423, 1985)
- Time Quake (with Chris Lowder, in Starlord #1-13, 1978)
- Thriller Picture Library
- Battle Picture Weekly
- Blake's 7
- Jeff Craig Detective
- Tiger McTaggart
- Typhoon Tennyson
- Dan Dare
- Untitled (in Eagle Annual 1979, 1978)
- Return of the Mekon (with B. J. Tomlinson, John Wagner and Pat Mills, in Eagle #19-26, 1982)
- The Dare Report (with Pat Mills, in Eagle #34-38, 1982)
- Fireflight (with Pat Mills, in Eagle #39-83, 1982)
- Dan Dare