THE EQUALIZER
Who knew that a guest shot on MIAMI VICE would lead to an Also Starring credit on THE EQUALIZER? According to this website, Mickey Kostmayer was originally a one-off character, written with Keith in mind.  Then he was brought back for the episode Bump And Run and the rest is history; he appeared in 41 (counting two part episodes as two) of the 88 episodes.  Here's a list of the episodes, by season.
Season 1:  Keith only appeared in four episodes:  China Rain, Bump and Run, Dead Drop and Breakpoint.  Interestingly enough (well, I thought so, anyway) Marice Hurley and Joel Surnow wrote the first three listed (Victor Hsu also worked on China Rain, mentioned in Story by).  Scott Shepard and Don Carlos Dunaway are listed as the writers for Breakpoint.  Note: Mickey Kostmayer was mentioned in The Distant Fire (two episodes before Bump and Run) and Torn.

Season Two
:  The Cup, Heartstrings, High Performance, Beyond Control, Carnal Persuasion, Memories of Manon 1 & 2, Re-entry.  Mickey was also mentioned in the second season premiere Prelude then later, in Counterfire.  Note, Keith Szarabajka was busy filming a movie WHEELS OF TERROR AKA THE MISFIT BRIGADE so he wasn't available for filming when the second season started, that's why Mickey didn't show up until the tenth episode of the season.

Season Three: 
Blood & Wine, 1 & 2, In The Money, (note:  these three episodes, as well as Suspicion of Innocence and Encounter in a Closed Room were filmed before Edward Woodward suffered a double heart attack in Britain, during the filming of Codename: Kyril.  Five in all were filmed before Season Three was officially supposed to start filming.  CBS wanted a name actor, so Richard Jordan was brought in.  Again,  more can be read at the website I've linked above, both in Supporting Actors, and the episode guide for the show.)  Mission: McCall 1 & 2, Shadow Play, Something Green, No Place Like Home, Last Call, Regrets Only, Target of Choice, Always A Lady.  Mickey was mentioned but not seen, in Suspicion of Innocence and Encounter in a Closed Room.

Season Four: 
Sea of Fire, Riding the Elephant, Eighteen With a Bullet, Day of the Covenant, Splinters, The Making of a Martyr, The Sins of our Fathers, The Visitation, Past Imperfect, Trial By Ordeal, Silent Fury, Lullaby of Darkness, Starfire, Time Present, Time Past, Prisoners of Conscience, Race Traitors and Endgame.  Mickey was also mentioned in 17 Zebra and The Caper.

Pretty good for a character meant to be in only one episode. :)
Index Keith 1 page David McCallum
Equalizer 2  Keith 2  Geoff Paine  books
music Andrew McFarlane  Kristoffer Tabori
Keith Wallpapers, 2 and 3
Mickey in action in China Rain and one of my fave vidcaps, from Starfire, all pics courtesy of TinaM.
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