Neil Patrick Harris only began appearing in TV as an adult.
Doogie Howser , M.D. is an American comedy-drama television series that ran for four seasons on ABC from September 19 , 1989 , to March 24 , 1993 , totaling 97 episodes . Created by Steven Bochco and David E. Kelley , it stars Neil Patrick Harris in the title role as a teenage physician who also faces the problems of being a normal teenager . Neil Patrick Harris . On television , he is known for playing the title character on Doogie Howser , M.D. ( 1989 -- 1993 ) , Barney Stinson on How I Met Your Mother ( 2005 -- 2014 , for which he was nominated for four Emmy Awards ) , and Count Olaf on A Series of Unfortunate Events ( 2017 onward ) .