Conversation so far:
What did Phil Hartman do in Phil Hartman's early career?
Working alone as a graphic artist, Hartman frequently amused himself with "flights of voice fantasies".
What did he do as a graphic artist?
CANNOTANSWER.
What were the voices he did to amuse himself?
Hartman recorded a number of voice-over roles.
These included appearances on The Smurfs, Challenge of the GoBots.
What other shows was he on?
Hartman co-wrote the script of the 1985 feature film Pee-wee's Big Adventure and had a cameo role.
Did he write anything else?
Pee-wee Herman and developed The Pee-wee Herman Show.
How long did he work on the show?
Although he had considered quitting acting at the age of 36 due to limited opportunities, the success of Pee-wee's Big Adventure brought new possibilities and changed his mind.
What were the possibilities?
After a creative falling-out with Reubens, Hartman left the Pee-Wee Herman project to pursue other roles.
What other roles did he take on?
Additionally Hartman developed a strong persona providing voice-overs for advertisements.
Are there any other interesting aspects about this article?
While watching one of the troupe's performances, Hartman impulsively decided to climb on stage and join the cast.

Question: What happened after that?
Self-contained rewrite: What happened after Phil Hartman climbed on stage to join the cast?