I've been having fun digging through the ranks of Konami's Kukeiha Club, amongst other composers to have worked for them over the years. Here's a list of the major ones, with mini bios and links to their websites. Forgive me for any errors - I'm working sources from both the English and J-Wikipedia, as well as Mobygames and any other place that has credits, so some of it may be incorrect. I do find it interesting how many old timers are still with Konami, with many of them working on the Beatmania series and other rhythm games.
Motoaki Furukawa AKA Michelle Furukawa
One of the old-school folk, Motoaki Furukawa contributed to Gradius II, A-JAX, Super Contra, Castlevania, XEXEX, Castlevania 64, Lethal Enforcers, Policenauts, and Sunset Riders. He's put out a few solo arrange albums, including one, Under the Blue Sky, that includes music from Gradius, amongst others, and nowdays spends a lot of time with Konami's rhythm games. He also contributed a few tracks to Thunder Force VI.
Michiru Yamane is mostly known for her work on the Castlevania series. Her first work on the series was Castlevania: Bloodlines, but her Symphony of the Night soundtrack won her accolades from around the globe. She also did Aria of Sorrow, Lament of Innocence, Portrait of Ruin (along with a few songs from Yuzo Koshiro), Order of Ecclesia (with the help of Yasuhiro Ichihashi), Curse of Darkness, and contributed to Dawn of Sorrow, Dracula X Chronicles, and Harmony of Dissonance.
Ms. Yamane worked on several earlier titles long prior to Castlevania though. These include Asterix (Arcade), Crime Fighters 2, Detana Twinbee, Teenage Mutant Ninja Turtles: Fall of the Foot Clan for the Gameboy, Motocross Maniacs, SD Snatcher, Ganbare Goemon 2, Cowboys of MOO Mesa, and Rocket Knight Adventures. In the post 16-bit days, she also suppled work for the PSOne games Gungage (not her best work) and Elder Gate, and JP/EU-only PS2 game OZ: Over Zenith/Sword of Etheria (actually quite good.) She also contributed a few tracks to Suikoden III and IV, and Elebits.
Miki Higashino - MIKICHANG
Ms. Higashino is most well known for her work on the first two Suikoden games, which are largely regarded to be the best of the bunch. Her work stretches back pretty far, to Gradius, Salamander, Life Force, Knightmare, Gradius III, and Contra 3. She also did Vandal Hearts and recently contributed a few tracks to Otomedius.
You'll recognize a Sota Fujimori tune if you hear it - the man loves house, trance and dance music. As a result, he's one of the main guys in charge of Dance Dance Revolution and Beatmania music. He helped Michiru Yamane with Gungage, did the newly arranged versions for the PSOne remake of Akumajou Dracula X68000 (Castlevania Chronicles), and did all of the non-heavy metal tracks for Contra: Shattered Soldier. That last gig earned him the full time job of composing the entire Neo Contra soundtrack, which accounts for the change in style between the games.
Akira Yamaoka is the man behind the Silent Hill music. Although most of those soundtracks consist of industrial grinding and other environmental effects, his guitar-based themes, used in intros and endings, are also quite distinct. From the third game on, he also uses a lot of vocals, sometimes to unintentionally cheesy effect, something of a talent for Konami's musicians.Starting at the third game in the series, he began directing the Silent Hill games in addition to writing the music. He technically supplied the soundtrack to the film version, although it mostly just consisted of renditions from the games anyway. Eventually Konami starting farming the Silent Hill games to outside (Western) companies, but Yamaoka still supplies the music. In addition to Silent Hill, he also composed most of the music in Contra: Shattered Soldier, which has an extremely loud, extremely heavy rock soundtrack. His solo album, iFutureList, is quite excellent and worth a listen. Some of his tracks also appear in DDR and Beatmania stuff.
One of the composers of Castlevania 64, as well as Dawn of Sorrow, and contributor to the Suikoden III & IV soundtracks. He seems to do slow, piano-based themes very well.
Another name from the early days of Konami, Mr. Takenouchi contributed to Space Manbow, Mystic Warriors, Quarth (MSX version), Metal Gear 2, X-Men and Gaiapolis. At some point he left and became responsible for the Bravo Music (AKA Mad Maestro) series. He's supplied music to a few other games, most notably the PS2 cult hit Chane Dive, Namco's Ace Combat X, and From Software's recent PS3 RPG Demon Souls.
Naoki Maeda - Ensonique Maeda, Daamae
Like Fujimori, Naoki Maeda spends a lot of his times with Konami's rhythm games - anything you see a "NAOKI" version, it's by him. He's also apprently the guy behind Be4U, the girl band created by Konami specifically to promote (and supply music for) their rhythm games. Before his work on these, he also composed the soundtracks to Yahho! Twinbee and Salamander 2, both of which are outstanding.
Kimeyo Yamashita - yamako
This young woman is responsible for the soundtrack to Castlevania, providing the basis for some of Konami's most memorable music. She also composed (or contributed to) Moero!! Twinbee (Stinger), Almana no Kiseki, Hi no Tori (Firebird/Phoenix), Esper Dream, and King Kong 2. She left Konami early on and went freelance, but worked on several other notable games, including Captain Saver (Power Blade), which accounts for its curiously excellent soundtrack, and Megaman X3. She apparently also did/does a lot of works on the Medabots games.
Kenichirou Matsubara - KEN, Taurus Matsubara
Going hand in hand with Ms. Yamashita, Ken Matsubara is responsible for Castlevania II's soundtrack, again, one of the highlights of their 8-bit output. He also did the arcad game Haunted Castle, which accounts for the reason that they both share a few of the same songs. He also worked on a few other games, notable Penguin Adventure, Gradius II, Trigon, Wai Wai World 2, Crisis Force, Contra Force and Twinbee Rainbow Bell Adventure.
Tsuyoshi Sekito - Zenji Pekito
So this is pretty interesting - three of Square-Enix's current composers originally got their start at Konami. Tsuyoshi Sekito worked on early MSX games like Space Manbow, SD Snatcher and Metal Gear 2, as well as TMNT 2: The Arcade game and TMNT 3: The Manhattan Project for the NES. Upon his defection to Square, he started with Brave Fencer Musashi, and moved on to Romancing SaGa: Minstrel Song and The Last Remnant. His style on these games fits closely to Kenji Ito, the previous composer of the SaGa games.
Kenichirou Fukui worked on several early 90s arcade games, including Sunset Riders, Lethal Enforcers, GI Joe, Violent Storm and XEXEX. His first work at Square was the excellent dark techno soundtrack Einhander. He disappeared into the background for awhile, mostly doing soundtrack, but he also ended up contributing to Front Mission 5, Hanjuku Hero 4 (neither of which came to America) and Project Silpheed.
Junya Nakano seemed to work in the same period as Fukui and Sekito, supplying music for X-Men, Asterix and Mystic Warriors. Upon his departure to Square, he headed up Dewprism (Threads of Fate), collaborated with Masashi Hamauzu and Nobuo Uematsu with Final Fantasy X, and did work on Musashiden II and Project Silpheed.
Tappi is mostly known as the guy behind the Metal Gear Solid theme (the same one that was purportedly ripped off from a Russian composer.) Before that, he worked with Hideo Kojima on the Policenauts soundtrack (perhaps he also composed that haunting 14-note theme that's the core of Policenauts soundtrack and plays on the Konami logo in MGS.) He also supplied music for Suikoden II, Lethal Enforcers, and Contra III.
Hibino first collaborated with several other composers on Zone of the Enders (and eventually its sequel), but he also did much of the music for Metal Gear Solid 2, 3 and 4. In his interviews, he was apparently annoyed that "big name" Hollywood composer Harry Gregson-Williams was often given first (and in some instances, only) billing for soundtrack composition, when he really only did the cutscenes. Hibino was freelance by the time MGS4 came out, starting up the company GEM Impact, and has since done other works, including 1942: Joint Strike for the XBLA and PSN and Ninja Blade for the Xbox 360.
Taro Kudou - Souji Taro
The composer of two of Konami's best SNES OSTS - Super Castlevania IV and Axelay - left Konami and apparently went into development with Square, then went to work for Love-de-Lic and eventually Vanpool. He's credited with working on Super Mario RPG, as well as Tingle's Freshly-Picked Tingle's Rosy Rupeeland
One of the composers for Castlevania III also did the NES Tiny Toons games, along with Contra Force and Batman Returns. Eventually he got promoted to a music director at Konami's Hawaii office, which mostly did DDR and Frogger stuff.
Another one of Konami's early legend, Maezawa composed music for the NES version of Contra, Super C Teenage Mutant Ninja Turtles and Life Force. He also contributed to Castlevania III and designed the VRC6 memory mapper chip, which allowed for extra sound channels in Famicom games. He also did the music for the original Parodius - apparently he was given such a short time to write it, that he just cribbed various public domain classical and folk songs, which ended up becoming one of the highlights of the entire series.
Yet another old-timer, Izumi worked on Snatcher, SD Snatcher, Metal Gear 2, Asterix, TMNT (Arcade), TMNT (NES), TMNT Turtles in Time, Metamorphic Force, Speed King, Crime Fighters, and Solar Assault. He mostly does work on the Beatmania series and its associated games, particularly Guitar Freaks.
Norio Hanzawa - NON
Norio Hanzawa was not at Konami long - he worked on the MSX version of Quarth, Rollergames, and both Castlevania Adventure games, which happen to be some of the finest soundtracks for the little system. He later defected along with Masato Maegawa and a few other to form Treasure, where's been one of their lead musicians ever since. There, he worked on Gunstar Heroes, Guardian Heroes, Dynamite Headdy, Alien Soldier, Mischief Makers, Bangai-O, Bleach: Blades of Fate, and many others.
Mikio Saito - Metal Yuuki
Mikio Saito defected from Tecmo, where he had composed the arcade versions of Ninja Gaiden and Rygar. At Konami, he's mostly known for Thunder Cross II, contributing to Akumajou Dracula X for the PC Engine, and tons upon tons of Tokimeki Memorial stuff.
Here are some other Konami composers, whom I couldn't come up with any other interesting biographies for:
Seiichi Fukami - FUKA
Gradius II (Famicom)
Bio Miracle Bokutte Upa
The Adventures of Bayou Billy
Life Force (NES)
Graidus II (Famicom)
Gofer no Yabou (MSX)
Gradius III (SNES)
Twinbee Rainbow Bell Adventure
Akumajou Densetsu (Castlevania III)
Tiny Toon Adventures: Babs' Big Break
Castlevania II: Belmont's Revenge
Skate or Die: Bad 'N Rad
Castlevania: The Adventure
Yume Penguin Monogatari
Majou Densetsu 2
Gofer no Yabou Episode 2
Muchi Muchi Brin - KO
Wai Wai World 2
Boku Dracula-kun (Kid Dracula)
Tiny Toon Adventures
Junichirou Kaneda - J_KANE
'Nyan Nyan Panic
Zen Intergalatic Ninja
TMNT Tournament Fighters (SNES)
Ring of Red