The Walking Dead began in 2010 with their first season. After that, each year there has been another season. So, there are 9 seasons so far, but there are future seasons in the works. Seasons 11 and 12 seem to already have some thoughts put into them. The last episode aired for the first season on December 5, 2010. There were six episodes in the first season.
There were thirteen episodes in the second season. There were sixteen episodes in the next several seasons including seasons three through season eight. So far there are sixteen in the ninth season but the last episode has yet to air. The first season begins with the policeman waking up to zombies after being in a coma.