David, also known as David the Scientist Guy, was the first serious love interest of Phoebe Buffay. Their romance ended when David had to go to Minsk to work.
David's dialogues are characterized by his lack of fluency in speaking (his lines are often punctuated by stutters and 'um's), a fact which Chandler brings out to Monica in "The One In Barbados, Part 1".
David was first featured in "The One With The Monkey", Phoebe yells at him when his loud conversation with fellow scientist Max interrupts her guitar playing. When David explains that they were talking about how beautiful she was, all is forgiven and she now wants to break the New Year's "no date" pact. Unfortunately, David is torn because he and Max were given a grant to study in Minsk. Max mistakenly claims Minsk is in Russia, while it really is in Belarus. Eventually, he leaves, and Phoebe is left heartbroken. He returns in Season 7's "The One With All The Cheesecakes" to visit, and Phoebe has to decide between seeing him during the one night he'll be there, or keeping her dinner with Joey. She does the former, despite lecturing Joey for doing the same thing. He then returns during the latter half of Season 9 after failing in his research in Minsk. He professes his love for Phoebe, but she has moved on to Mike by this time, and she eventually accepts Mike's proposal for marriage.
- David is portrayed by Hank Azaria, who is one of three voice actors from the animated sitcom The Simpsons to appear on Friends. The other two were Harry Shearer, who portrayed Dr. Baldharan and Dan Castellanata, who portrayed The Zoo Employee .
- David is played by Hank Azaria, who also plays Nat Ostertag in Mad About You, however both of these shows exist in the same universe, as Phoebe's twin sister Ursula appears on Mad About You and two main characters of Mad About You appear on Friends mistaking Phoebe as Ursula.