Local soccer aficionados may remember the glory days of the Timbers—the 1970s and early 1980s, when Portland was known as Soccer City USA. With players such as Clyde Best, Stewart Scullion, and Peter Withe and coaches Vic Crowe and Don Megson, the Timbers packed Civic Stadium with fans. In its first year, the team made it to the Soccer Bowl, the North American Soccer League's version of the Super Bowl.

The NASL was created in 1968 with the merger of the United Soccer Association and the National Professional Soccer League. As U.S. fans warmed to the sport that was so successful abroad, the league expanded in 1975 to include the Timbers.

Soccer was an instant success in Portland. The inaugural season included victory in New York against the Cosmos, the NASL's highest-profile team, and the Timbers drew several crowds in excess of 20,000. They ended the regular season with a 16-6 record. Portland scored playoff wins over Seattle and St. Louis on their way to Soccer Bowl'75, where the Timbers fell 2-0 to the Tampa Bay Rowdies.

After two down years, the Timbers had another big season in 1978. They had a 20-10 record through the regular season and won two playoff rounds before losing to the Cosmos in the semifinals.

The Timbers would make the playoffs one more time, in 1981, dropping a best-of-three series to San Diego, 2-1. By 1982, attendance figures had fallen dramatically, and the franchise folded after that season.

In 2001, Portland became an entry in the United Soccer Leagues First Division, a second-tier professional league in the U.S., and took the name of the Timbers. Interest in the club slowly built until 2007, when Merritt Paulson led a group that purchased the Timbers, along with the minor-league baseball team, the Portland Beavers.

In 2009, the Timbers were granted an expansion franchise in Major League Soccer, contingent on construction of a soccer-only stadium. Renovation of PGE Park—now called Jeld-Wen Field—was completed in early 2011 at a cost of $31 million. The Timbers sold all 12,500 season tickets for home games during the 2011 campaign, which began March 19 with a 3-1 loss at Colorado.

The Timbers won their first Major League Soccer championship on December 6, 2015, when they beat the Columbus Crew 2-1 in the MLS Cup final at Columbus, Ohio. Diego Valeri—who won match MVP honors—scored a goal 27 seconds into the game to give Portland the lead, and Darlington Nagbe provided the game-winner. It was a glorious end to the team's first title campaign in nearly forty years of professional soccer in Portland. Following a rocky mid-season, the Timbers won four of their final five regular-season games, then knocked off Sporting Kansas City, the Vancouver Whitecaps, and FC Dallas on the way to the crown. Two days later, 20,000 people showed for a celebration and parade in downtown Portland.

The Timbers made the MLS Cup final in 2018, losing to Atlanta United, 2-0. During the COVID bubble in 2020, Portland played their way into the championship game of the MLS is Back Tournament and defeated Orlando City SC, 2-1. Timbers midfielder Sebastián Blanco was named the best player of the tournament. In 2021, Portland again made the MLS Cup finals, losing at home against New York City FC in a heartbreaking penalty shootout. The end of that season marked another ending for the club, when Timbers midfielder Diego Valeri, one of the most accomplished and popular players in the MLS, retired from the league. Named MVP of the 2017 MLS season, Valeri scored a club record 100 goals and set a Timbers’ standard with 104 assists in his nine seasons in Portland.

In 2022, the club faced national controversy with the release of the Yates Report, which accused executives Gavin Wilkinson and Mike Golub of covering up and making misleading statements about verbal and sexual abuse by former Portland Thorns manager Paul Riley. That, and evidence of the club’s mishandling of allegations of off-field domestic abuse by Timbers players, led to an overhaul of the front office—the first in the Timbers’ MLS era. Wilkinson and Golub were fired, team owner Merritt Paulson stepped away from day-to-day operations of the club, and Heather Davis was named CEO in January 2023. Alaska Airlines, a kit sponsor for thirteen seasons, ended its sponsorship in 2023; Tillamook stepped in for the 2024 season after an agreement with DaBella Exterior was scrapped.

The 2023 season was unremarkable, with 11 wins, 13 losses, and 10 draws. The Timbers did not qualify for the MLS Cup playoffs. Coach Giovanni Savarese, who had been with the club since 2018, was let go midway through the season. He was replaced by Phil Neville for the 2024 season. In January 2024, RAJ Sports acquired controlling ownership of the Portland Thorns from Paulson's Peregrine Sports, LLC.