Welts began his NBA career as a ball boy for his hometown Seattle SuperSonics in 1969. He soon became an assistant trainer for the team and after college became the assistant director of public relations. He headed Seattles public relations during back-to-back appearances in the NBA Finals in 1978 and 1979, the latter becoming Seattles only NBA championship.
In 1982 Welts joined the National Basketball Associations league offices as Director of National Promotions. He later became Vice President for Communications and eventually the leagues third-in-command as Executive Vice President, Chief Marketing Officer, and President of NBA Properties. During his time with the NBA, Welts was a key part of the leagues revitalization and resurgence. In 1984, Welts created the NBA All-Star Weekend, which was quickly replicated across professional sports. In 1992, he ran the marketing for USA Basketballs Olympic Dream Team; in 1996 he helped launch the WNBA.
Weltss talk is a part of the Athenaeums ongoing series Shifting Perceptions: Celebrating the Spectrum of Leadership, which aims to foster a greater sense of inclusivity and community at CMC by celebrating the bold leadership of women, gay men, and lesbians. The series is sponsored by nine different offices and organizations on campus, including the Athenaeum, the Presidents Office, Dean of Students, and the Dean of the Faculty.