In 1965, however, a plum comedy role came Matthau's way when Neil Simon cast him in the hit play The Odd Couple playing the slovenly sportswriter Oscar Madison opposite Art Carney as Felix Unger.

Duos of equal importance on TV such as Kate McArdle and Allie Lowell ( Kate & Allie ), Oscar Madison and Felix Unger ( The Odd Couple ), Bret Maverick and Bart Maverick ( Maverick ), Captain Scarlet and Captain Blue ( Captain Scarlet and the Mysterons ), or Laverne De Fazio and Shirley Feeney ( Laverne & Shirley ), are sometimes both called sidekicks to each other, although the usual sense of the term denotes inequality.

His subsequent Broadway appearances included his portrayal in 1965 – 67 of Felix Unger in The Odd Couple ( opposite Walter Matthau and then Jack Klugman as Oscar ).

Leif also played the role of Leonard Unger, the son of Felix Unger ( Tony Randall ), on the ABC series The Odd Couple, a part that previously was played by Willie Aames.

He also appeared as Felix Unger in a stage version of Neil Simon's The Odd Couple with Art Carney as Oscar Madison.

In 1971, he originated the role of Leonard Unger, the son of Felix Unger ( Tony Randall ), on the ABC-TV series The Odd Couple, a part that was later played by Leif Garrett.

Wilson later starred as divorcé Raymond Ellis in the short-lived CBS-TV comedy series Baby, I'm Back and as Oscar Madison, opposite actor Ron Glass ( who co-starred as Felix Unger ) in the ABC TV sitcom The New Odd Couple, a revamped black version of the original 1970-75 series on the same network which starred Jack Klugman and Tony Randall.

After a long hiatus from the medium, he returned in 1970 as fussbudget Felix Unger in The Odd Couple, opposite Jack Klugman, a role he would keep for five years.

In September 1993, Randall and Jack Klugman reunited once again in the CBS-TV movie The Odd Couple: Together Again reprising their roles as Felix Unger and Oscar Madison.

He would often chide Johnny Carson for his chain-smoking, and was generally fastidious and fussy, much like his Felix Unger characterization.

Felix Unger ( or Ungar ) was one of the principal characters in Neil Simon's play The Odd Couple.

* Janis Hansen, actress who played Gloria, wife of Felix Unger, on The Odd Couple.

* Ron Glass … Felix Unger

* Felix Unger, fictional character in The Odd Couple

It's been 17 years since Oscar Madison and Felix Unger have seen one another.

* Jack Lemmon as Felix Unger

He played Felix Unger in three performances on July 24 – 26.

The European Academy of Sciences and Arts was created in 1990 in Salzburg, Austria by heart surgeon Felix Unger of Salzburg ; the cardinal archbishop of Vienna, Franz König ; and the political scientist and philosopher Nikolaus Lobkowicz.