Rapps never made it to the highest level of professional baseball, which several sources throughout his career attributed to his behavior and lackadaisical play.

Following his retirement, Rapps worked on his farm and operated grocery and feed stores in Schell City, Missouri, and Iola, Kansas.

[9][10] Around 1900, Rapps was employed by W. H. Drumheller in Centerville, Missouri, and played shortstop for an amateur town baseball team in Erie from 1900–01.

[13] By 1904, Rapps had begun antics that would become a staple throughout his baseball career; his loud shouting and noise-making — which earned him the nickname "Noisy Bill".

[18] He was moved defensively from the outfield to the infield, which The Topeka State Journal noted improved Rapps' fielding percentage.

[19] Rapps was acting as third base coach during a game on May 3, 1904, when his actions caused a Leavenworth baserunner to be called out due to a league rule against "foolishness".

Rapps was late reporting to the Orioles, but eventually joined the team in June 1905 after the Leavenworth management increased his salary.

[26][27][28] The Topeka State Journal asserted in their August 10, 1905, edition that Rapps' "idiosyncrasies" kept him from being promoted to a higher minor league.

[31] After the season, Rapps joined the Sedalia Goldbugs on a month-long tour of Oklahoma where they played local amateur and semi-pro teams.

In April 1907, Rapps was traded by the Wichita Jobbers to the Oklahoma City Mets in exchange for Affy Wilson.

[13] Before the 1910 season, Rapps was drafted from the Kansas City Blues by the Portland Beavers of the Class A Pacific Coast League.

[9] Rapps would later admit to sending a positive scouting report of himself via telegram to Portland manager Walt McCredie under a false name.

[10] The Oregonian's W. J. Petrain wrote on March 17, 1910, "Billy Rapps, the lanky, dark complexioned first baseman, will win the hearts of the Portland fans from the very start.

[55] Following the 1910 season, Beavers' manager Walt McCredie announced Rapps would be returning as the team's first baseman.

[57] Rapps executed a hidden ball trick putout on Clarence McDonnell during the sixth inning of a game against the Vernon Tigers on September 17, 1911.

[58] During the tenth inning of a game against the Oakland Oaks on September 21, 1911, Rapps was struck on the top of the head by a pitch from Jack Flater.

[59] The following day, Rapps was called on to pinch hit in a tied 3–3 contest against Oakland in the ninth inning and drove in the winning run.

[61] Following the season, Rapps played on an indoor baseball team in Portland with Beavers teammates Bill Steen, Nick Williams and Art Kruger.

[63] Walt McCredie planned to meet with St. Louis Browns owner Robert Lee Hedges about a possible trade involving Rapps.

[70] In a game against the Oakland Oaks on September 14, 1912, Rapps completed an unassisted triple play, the third in the history of the Pacific Coast League.

[74] Walt McCredie announced in November 1912 that he intended to trade Rapps in order to make room on the Beavers' roster for the upcoming season.

[76] On February 12, 1913, The Oregonian reported that McCredie was working out a deal to send Rapps to the Waterbury Spuds of the Class B Connecticut State League.

[77] At the last second, the Topeka Jayhawks of the Class A Western League stepped in and made an offer of $600 for Rapps, which McCredie accepted.

[84] Rapps finished the season with a .261 batting average with 30 doubles, five triples and ten home runs in 148 games played.

[87] During one of the final games of the season in late September 1914, The Topeka State Journal wrote, "About the only highlights in the gloomy picture was furnished by Willie Rapps with his polite vaudeville.

[89] The cup was donated by and named for Topeka Mayor Jay E. House, who was a teammate of Rapps when they played for the Erie, Missouri town team in 1900.

[96] Jayhawks general manager John Savage assisted Rapps in trying to secure a managerial job, and gave him permission to seek out deals and negotiate on his own behalf.

[98] The Omaha Daily Bee reported on Rapps release, writing, "Topeka will be minus one of its drawing cards this year.

[111] Bill and Lillie Pearl Rapps celebrated their 57th wedding anniversary on April 7, 1965, at the McAtee Nursing Home in Iola.

[112] Bill Rapps died on April 20, 1965, in Iola and was interred at Green Lawn Cemetery in Schell City, Missouri.