The Brazilian axed Yokohama's Tatsuhiko Kubo in favour of Maki in a bid to solve Japan's recent goal drought.
The 25-year-old Maki's selection drew gasps at a packed news conference when Zico read his name out last in announcing the 23-man squad.
Zico kept faith with former Sampdoria striker Atsushi Yanagisawa, who is still recovering from a broken metatarsal, and German-based forward Naohiro Takahara.
Celtic's Shunsuke Nakamura and Hidetoshi Nakata of Bolton Wanderers are among an experienced group of midfielders for the World Cup in Germany.
Nakamura was left out of Japan's 2002 World Cup squad by former coach Philippe Troussier, while Takahara missed out after being struck down by a mystery lung infection.
"This is a team for the people of Japan -- a team the country can be proud of," Zico told reporters.
"We expect to be judged on our results. The buck stops with me."
Zico added that surprise call-up Maki, who has scored three goals in nine appearances for Japan, could be the team's X-factor in Germany.
"Kubo was not right physically and Maki is an interesting player who gives us another option," the 53-year-old old.
"He's shown he can be a threat in the penalty box."
Even Japan Football Association president Saburo Kawabuchi admitted to being shocked by Maki's inclusion.
Eleven of the 23 were among the Japan squad who reached the last 16 under Frenchman Troussier as co-hosts four years ago.
Japan face a tough assignment to match that achievement, having been drawn alongside holders Brazil, Australia and Croatia in Group F.
"I have faced a lot of criticism in the last four years but I've done the job to the best of my ability and I think you will see the best of Japan in Germany," Zico added.
"Selecting this squad was the hardest thing I've done but it's the result of four years of work. I have faith in this group of players and confidence they will do the job asked."
The Asian champions, who will be appearing in their third straight World Cup finals, face Guus Hiddink's Australia in their opening game on June 12.
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Goalkeepers - Yoshikatsu Kawaguchi (Jubilo Iwata), Yoichi Doi (FC Tokyo), Seigo Narazaki (Nagoya Grampus Eight)
Defenders - Tsuneyasu Miyamoto (Gamba Osaka), Alex (Urawa Reds), Yuji Nakazawa (Yokohama F-Marinos), Makoto Tanaka (Jubilo Iwata), Akira Kaji (Gamba Osaka), Keisuke Tsuboi (Urawa Reds), Yuichi Komano (Sanfrecce Hiroshima), Koji Nakata (FC Basel)
Midfielders - Hidetoshi Nakata (Bolton Wanderers), Shunsuke Nakamura (Celtic), Shinji Ono (Urawa Reds), Junichi Inamoto (West Bromwich Albion), Takashi Fukunishi (Jubilo Iwata), Mitsuo Ogasawara (Kashima Antlers), Yasuhito Endo (Gamba Osaka)
Forwards - Atsushi Yanagisawa (Kashima Antlers), Naohiro Takahara (Hamburg), Masashi Oguro (Grenoble), Keiji Tamada (Nagoya Grampus Eight) Seiichiro Maki (JEF United Chiba)