improvisationalist

And his Comedy Central colleague Stephen Colbert is probably the quickest and most alert improvisationalist on the air.

TV: Culture and Celebrity Scheyer, Kate 2009

Having grown up without a father and as an adult essentially friendless, Scott as portrayed by Carell derives virtually all of his opaque identity from his job at the office, a platform from which he tries to act out his improbable dreams, which range from the pedestrian one of merely having a friend to more rococo concoctions, like being a standup comedian, an improvisationalist, or an emcee.

Slate Magazine Bill Wyman 2011

Morales 'ball flew into the left-field corner, and Morales easily won a battle of his old legs and Brett Butler's weak arm, cruising into second with a stand-up double, and giving the master improvisationalist, Scully, his modest opening line ...

Dodger Thoughts 2008