McCallum began his professional acting career in 1957, with roles in four movies: These Dangerous Years, Robbery Under Arms, Hell Drivers and The Secret Place. Since then he has gone on to have roles in movies like Casino Royale, Healer and Cheery. In total, he has appeared in over 30 movies. His television credits include The Outer Limits, The Invisible Man, As The World Turns, The A Team and Babylon 5, with a total of over 20 television credits.

1. "In a few hundred years you have achieved in America what it took thousands of years to achieve in Europe. Mind, you borrowed some things, but the American way of life has a different pulse, the pulse of what's going on. I like that." $mdash; David McCallum on America
2. "I came to New York once and I'd never been in Central Park. I went for a walk and it took two police on horseback to rescue me. There was a form of insanity about it all.... it was scary and it was enjoyable." mdash; David McCallum on fans
3. "I love what he does, I like the humour of his mind. I like the fact that he that he rambles on but, more than that, he's given me the opportunity to learn so much." — David McCallum on his character Ducky Mallard