[3] He grew up in Japanese-controlled Palau and joined the Kempeitai, the Japanese secret police, during World War II.

He worked in the Congress of the Trust Territory of the Pacific Islands from 1964 to 1978 and advocated for Palau gaining a separate status from the rest of Micronesia.

As a businessman, Tmetuchl led several construction projects for his business holdings and for the Palauan community, including the Palau International Airport (which was later renamed in his honor) and a Seventh-Day Adventist clinic.

In 1948 he traveled to Guam for further training and testified at a war crime trial for twenty Imperial Japanese Army personnel.

[5]: 65  Throughout the 1950s and early 1960s he worked in Trust Territory of the Pacific Islands (TTPI) positions such as translator, public defender, counselor, administrative assistant, and district court judge.

He served from 1969 to 1970 on House committees and congressional groups regarding future political status and budget planning.

A man named Heinrich Ngowakl stated that he was tasked by Tmetuchl's political opponent John O. Ngiraked to carry out the assassination, but soon realized he could not personally do it and so he gave the gun to Hitler.

[5]: 82–85  Senator Ambilos Iehsi filed a minority report questioning the election's results by noting an irregularity in the write-in votes.

[5]: 88 In 1974, Tmetuchl led Palau's newly formed Select Committee on Development and supported a bill which would allow Palauans to write their own constitution.

[4]: 32  A 1975 editorial in the Palauan newspaper Tia Belau criticized Tmetuchl's new position, calling it "out of tune" with local opinion.

[5]: 110–111  Tmetuchl and the PPSC attended the United Nations Trusteeship Council in July 1976, and then flew to Washington, D.C., to discuss Palauan separate status negotiations.

[5]: 147  Groups supporting Palauan unification with other Micronesian districts petitioned the government to expel Tmetuchl from his senate seat.

Tmetuchl stopped supporting the Compact of Free Association and used his power in the senate to oppose Remeliik's administration.

[12] Faced with political defeat once again, Tmetuchl decided to focus on his business holdings and his family life.

[5]: 118 Tmetuchl owned various businesses throughout his life, including real estate, several restaurants, a travel agency, and a hardware store.

The village of Ngchesar issued a public apology for the ordeal and Tmetuchl sponsored a party for the workers.

Ibedul Ngoriakl re-located the construction of his office to the site of a chief's meetinghouse and allowed Tmetuchl to retain his previous damaged project.

[5]: 37  In 1983, Tmetuchl met the businessman Masao Nishizono in Japan, and they became business partners to build an airport terminal and hotel in Airai.

[5]: 33  While serving as governor of Airai in the 1980s, he led projects to create a clan house and four modern-style bais, or a men's meetinghouses.

[5]: 45  In 1997, he led a construction project that built a Sabbath School building adjacent to the Seventh-day Adventist Church.

"[13][14] In 2008, the Tmetuchl family built a chapel at Belau National Hospital to honor and continue Roman's legacy.