Nelson Van Alden

Nelson Van Alden is noted for being one of the few characters to have multiple arcs throughout the series, motivated by a downward spiral of going from lawman to criminal.

At the start of the series, Van Alden acts as Nucky Thompson's (Steve Buscemi) primary antagonist, as he takes the lead to bring the kingpin down. However, in the midst of trying to tackle one of Prohibition's most notorious bootleggers, Van Alden's volatile temper and self-loathing start to blur his ethics; and by the end of Season 1, he has killed his corrupt partner Agent Eric Sebso (Erik Wiener) and violated his religious values through a one-night stand with Nucky Thompson's ex-mistress. Season 2 follows Van Alden's fruitless efforts to conceal his crimes from the previous season. The second season ends with Van Alden discovering he is the prime suspect in Sebso's murder, and he spends Season 3 on the run with his infant daughter and nanny Sigrid (Christiane Seidel) (with whom he later fathers a son), eventually settling in Chicago under the alias George Mueller. By the end of Season 4, Van Alden becomes an associate/muscle for Dean O'Banion (Arron Shiver) and eventually Al Capone (Stephen Graham), still going by the name George Mueller to avoid them discovering he is a former agent on the run.

The final season sees Van Alden struggling to keep the lifestyle of associate/muscle George Mueller balanced during his second failing marriage, this time to Sigrid. Van Alden has since been partnered with Thompson's brother Eli (Shea Whigham), who knows Van Alden's true identity. Mike D'Angelo (Louis Cancelmi), an undercover agent in Capone's crew, recognizes Van Alden, and both he and Eli agree to work with D'Angelo to help take Capone down. Van Alden also learns that Eli is having an affair with Sigrid. Eli and Van Alden eventually return to Capone's hotel to steal ledgers as proof of his tax evasion, but Capone's brother Ralph (Domenick Lombardozzi) becomes suspicious of their behavior. The Capone brothers confront them, with D'Angelo present, not knowing he is working undercover. With Van Alden's deteriorating home life and facing death at the hands of the Capones, he snaps and attacks the brothers while Eli and Malone watch in shock. In a rage, Van Alden confesses his true identity while choking Capone, but before he can successfully strangle him, Malone shoots and kills Van Alden in order to ensure that he is not exposed as a federal agent. The Capones then foolishly entrust Malone with the ledgers. Van Alden's death unwittingly leads to Capone going to prison for tax evasion.[2][3]

Nelson Van Alden has been frequently cited as a fan-favorite on Boardwalk Empire.[4] The role earned Shannon three nominations for the Screen Actors Guild Awards.[5]

• Agent Nelson Van Alden character bio at HBO.com