 Whedon approached Nathan Fillion to play the lead role of Malcolm Reynolds ; after Whedon explained the premise and showed him the treatment for the pilot , Fillion was eager for the role . Fillion was called back several times to read for the part before he was cast . He noted that " it was really thrilling . It was my first lead and I was pretty nervous , but I really wanted that part and I wanted to tell those stories . " Fillion later said he was " heartbroken " when he learned the series had been cancelled . Fillion has called his time on Firefly the best acting job he ever had , and compares every job he has had to it . 
