[5] By 1972, he had distinguished himself as a High School All American, placing third in the 200 freestyle at the AAU Metropolitan Championships in Roslyn, Long Island in July, 1972.

[9] Swimming at SMU from 1972 to 1976, he earned All-America honors in 1973 and 1974, was a four-time letter winner, and in 1973 captured the Southwest Conference Championship in the 400 IM.

Sinnott's ability to compete in multiple strokes including the individual medley made him more valuable to some future employers as a potential swim coach.

[11] Gaining valuable experience, Sinnott was an Assistant Coach at SMU from around 1980 to 1985 while the team finished in the top ten in the NCAA tournament in each of the years he was a staff member.

Sinnott replaced Bob Groseth as Head Coach at Iowa State in May 1988, but did not hold the position for long.

[4] In his most distinctive honor, Sinnott was a recipient of the 2019 National Collegiate Scholastic Trophy in 2019 by a vote of his swimming community peers.

In the summer of 2000, Lars Frolander became the fourth SMU swimmer to capture a gold medal at the Olympic Games, winning the 100 butterfly in Sydney, Australia.

He fought melanoma skin cancer in his final years, and died on February 20, 2024, in Stover among friends and family.