The Cascades were founded as WTT's charter franchise for San Diego, California in 1973, by orthodontist Dr. Leonard Bloom.

The Leis played nine of their 22 home matches at the Honolulu International Center and the other 13 at the Student Council Gymnasium on the campus of President William McKinley High School during the league's inaugural in 1974 season.

[7] Panui teamed with Kiyomura in mixed doubles on July 30, to take a set from David Lloyd and Ann Haydon Jones of the Minnesota Buckskins in a tiebreaker.

They added Owen Davidson (Minnesota Buckskins), Butch Buchholz (Chicago Aces) and Chris Evert (Florida Flamingos) in the dispersal draft.

Evert, who had not expressed interest in playing WTT in 1975, was traded to the San Francisco Golden Gaters for Margaret Court who sat out 1974, while she was pregnant but signed with the Leis for 1975.

[15][16] The Leis also added four local Hawaiian players: Heather Dahlgren, Stanley Pasarell, Peter Burwash and Jim Osborne.

The league used neutral-site matches to cut down on travel and create events where fans could see multiple teams either with one admission or over the course of a few days.

[16][17] Because of these and because of scheduling challenges created when the E-Z Riders suspended operations just days before the season started,[13] the 10 teams in the league did not play an equal number of matches.

The team's average home attendance was up 72% over the prior year, the second largest percentage increase in WTT, as of the mid-season Wimbledon break.

The announcement of the trade for and signing of Năstase was made at the WTT's 1975 draft at which the most noteworthy player chosen by the Leis was two-sport star John Lucas.

[24] On June 6, Leis president Don Kelleher announced plans to sue Năstase for breach of contract seeking $4 million in damages.

[29] The Cascades traded his rights to the Los Angeles Strings who gave him a six-year contract worth $1.5 million and two silver Corvettes.

[30] The Cascades did have success signing Betty Stöve whom the team had selected in the draft, after she was left unprotected by the San Francisco Golden Gaters.

[29] In February 1977, former Leis player Marcie Louie filed a lawsuit against the Cascades claiming breach of contract, libel, slander and invasion of privacy.

Loughman signed JoAnne Russell, Erik van Dillen, Patricia Bostrom and Steve Docherty as free agents.

On March 6, 1977, the Cascades landed another local player when they signed Tom Gorman who was ranked 12th in the world at the time and had played collegiate tennis for the Seattle Chieftains.

Russell teamed with former Leis player Helen Gourlay to beat Stöve and Martina Navratilova in the Wimbledon women's doubles final.

In league play, Gorman recorded two set wins over Björn Borg who was at the peak of his Hall of Fame career.

After home matches in Portland, the players were expected to catch the first commercial flight back to Seattle, because team president Kelleher refused to pay for hotel rooms for them.

[29] The Cascades finished the 1977 season with 18 wins and 26 losses, fourth place in the Western Division and secured the first playoff berth in franchise history.

[11][12] The Cascades went on the road for the first match of the best-of-three Western Division Semifinals and lost, 30–14, to a seasoned Phoenix Racquets team on August 16.

Billie Jean King and Ray Ruffels beat Stöve and Stewart, 6–2, to tie the match at 23 and send it to a super tiebreaker.

If you're working for them you shouldn't be saying anything.”" The Cascades won two of the next three points to win the super tiebreaker, 7–2, and earn the victory in the match.

[29] The Cascades finished the 1978 season with the best record in franchise history at 20 wins and 24 losses, fourth in the Western Division.

[11][12][29] The Cascades met the Western Division Champion San Diego Friars in the WTT Quarterfinals and dropped the first match in San Diego, 30–22, on August 15, losing four straight sets after Gorman and Stewart took the opening set of men's doubles from Rod Laver and Ross Case.

The Friars opened the match with a set win in women's doubles by Guerrant and Kerry Reid, 7–6, over Stöve and Cuypers.

Redondo fell behind, 3–1, and then rallied to win five straight games in women's singles against Kerry Reid to extend the Cascades' lead to 24–15.

Stöve and Kachel closed out the match with a mixed doubles set win against Raz Reid and Janet Young, 7–5, for a 31–20 victory.

"[4][35] Following the 1978 season, between October 27 and November 9, the New York Apples, Boston Lobsters, Los Angeles Strings, San Diego Friars and Indiana Loves all announced that they were folding, cutting the size of WTT from 10 teams to five.

[12] The following table shows regular season records, playoff results and titles won by the Seattle Cascades franchise since its founding in 1974.