Rubuta ci gaba don wannan sakin layi - An fitar da shi daga Quebec Major Junior Hockey League (QMJHL) na 22 a cikin 1998
, Gagné ya buga manyan matasa tare da Beauport Harfangs da Quebec Remparts na tsawon yanayi uku. Ya fara aikinsa na NHL tare da Flyers a 1999 kuma an kira shi zuwa NHL All-Rookie Team. Ya bayyana a wasanni biyu na NHL All-Star kuma ya lashe Bobby Clarke Trophies biyu tare da Flyers a matsayin MVP na kungiyar.