[5][6] Ozawa graduated from the Christian Academy in Japan[7][8] and has asserted that she has a higher ability to read and write English than Japanese.

[6] Ozawa also revealed she worked as a fast food server, a KTV bar attendant and a Japanese kindergarten school teacher.

[6] She began by modeling in June 2005 under the name Miyabi for the pornographic site Shirouto-Teien.com, which resulted in several sets of photographs and a short hardcore gonzo which was video released in CD-R and DVD-R formats.

[12] On October 7, 2005, she premiered as Maria Ozawa with the video New Face – Number One Style (新人xギリモザ ナンバーワンスタイル), directed by Hideto Aki.

The S1 video Hyper – Barely There Mosaic (ハイパーギリギリモザイク), featuring Ozawa along with other AV idols Sora Aoi, Yua Aida, Yuma Asami, and Honoka (plus a short preview for Rin Aoki), won first place.

[16] By the end of 2007, she signed (not exclusively) with Attackers (アタッカーズ), an established AV studio that specializes in thematic rape pornography.

Ran-maru, along with Ozawa's previous studios, S1, DAS and Attackers, are all part of Japan's largest group of AV companies, the Hokuto Corporation.

[29] Ozawa followed up on her Shinjuku experience by starring in a cabaret show, "Tokyo Nights" at the Grand Lisboa Hotel in Macau from August 16 to September 6, 2008, which also featured several other Japanese performers.

[30] XVN advertised in September 2008 about Maria Ozawa appearing in her first "uncensored" movies, which do not have the mosaic pixelation used to obscure the genitals in standard Japanese porn.

[45] In January 2009, Ozawa returned to DAS to film Shemale Orgy Gangbang Rape (集団ニューハーフ輪姦乱交レイプ小澤マリア) with three transsexual actresses[46] and in March 2009 entered the Japanese porn genre of tentacle rape with the video Monster Swallowing Ecstasy Maria Ozawa (触獣丸呑みアクメ 小澤マリア) for SOD.

[47] Her last adult video of 2010, Queen of Bukkake, Nakadashi, Gang Rape (女王様ブッカケ中出し輪姦ザーメン塗れの元S女), directed by Dragon Nishikawa, was released by Cross in April 2010.

[4] In November 2011, Ozawa co-starred with Asami and AV actress Mahiro Aine in Naoyuki Tomomatsu's science fiction V-Cinema release Karei naru erogami-ke no ichizoku: Shinsō reijō wa denki shitsuji no yume o miru ka,[49] which was also released with English subtitles as Erotibot.

[50] She was also cast in the starring role for the erotic horror V-cinema feature Tokyo Species which was released on DVD in February 2012.

[51][52] In October 2012, it was announced that Ozawa planned to engage in the Mainland China entertainment market on a full-time basis and was to sign with the media company Beijing Tuopu Laiyin.

[53] Ozawa visited the Philippines in April 2015 and made a guest appearance on the Manila radio show, Magic 89.9's Boys Night Out.

[58] She also announced that she would be co-starring with Filipino actor Robin Padilla in the horror-action film Nilalang ("Creature") which was due to start shooting in August 2015.