Major Roles:
* Doogie Howser, M.D. (1989-1993): His breakout role as a teenage prodigy doctor.
* How I Met Your Mother (2005-2014): Played the charming and lovable Barney Stinson.
* A Series of Unfortunate Events (2017-2019): Portrayed the sinister Count Olaf in this dark comedy adaptation.
* It's a Sin (2021): Played Henry, a friend of the main characters, in this acclaimed drama about the AIDS crisis in London.
* Uncoupled (2022-present): Currently stars as Michael Lawson, a recently-divorced man navigating the dating scene in New York City.
Recurring Roles:
* Starship Troopers (1997): Appeared as a soldier named Private Carl Jenkins.
* The Simpsons (2000): Guest-starred as a singing waiter in the episode "The Mansion Family".
* American Dad! (2009-present): Voices the character of Steve Smith.
* The Big Bang Theory (2010-2019): Had a recurring role as Barney the Stinson character.
Guest Appearances:
* The Muppets (1976-1981): Appeared in several episodes.
* Dr. Quinn, Medicine Woman (1993): Made a guest appearance as a young doctor.
* The West Wing (2000-2006): Played a guest role in an episode.
* Lost (2004-2010): Had a memorable guest appearance as a mysterious character.
* Glee (2009-2015): Guest-starred in several episodes as the hilarious Bryan Ryan.
This is not an exhaustive list, but it encompasses the most significant television shows Neil Patrick Harris has been involved in. He's known for his versatility and comedic timing, and has continued to take on diverse roles across a variety of genres.