The actor, who plays Captain Jack Harkness in Doctor Who and sister show Torchwood, said the Time Lord's latest incarnation was a more cheerful presence during filming.
He said: "I found the set to be a lighter one with David than it had been with Christopher in the lead role. I think David is a happier person, whereas I found Chris to be a bit angry."
However, he admitted that it had not all been plain sailing with Tennant because he struggled to avoid picking up his co-star's Scottish lilt.
Barrowman, who was born in Glasgow, said: "When David Tennant and I began filming together in early spring 2007, the hardest part for me was to resist speaking to him in a Scottish accent."
The actor recently revealed that he told his parents he was gay at the age of 21 after a serious AIDS scare.
> Click here for our interview with the cast of Torchwood