Tennant has done 3 series, as has every doctor since.

Eccleston: 1

Tennant: 2, 3, 4

Smith: 5, 6, 7

Capaldi: 8, 9, 10

Whittaker: 11, 12, 13

There are specials and other things that have included Tennant, but as far as being The Doctor for that series, he had 3.