diff --git a/packages/terra-navigation-side-menu/src/MenuItem.module.scss b/packages/terra-navigation-side-menu/src/MenuItem.module.scss
index d4f3134a95..4118e08d38 100644
--- a/packages/terra-navigation-side-menu/src/MenuItem.module.scss
+++ b/packages/terra-navigation-side-menu/src/MenuItem.module.scss
@@ -86,7 +86,25 @@
     }
 
     &.is-selected {
+      background-attachment: var(--terra-navigation-side-menu-item-selected-background-attachment);
       background-color: var(--terra-navigation-side-menu-item-selected-background-color, darken(#ebf6fd, 2%));
+      background-image: var(--terra-navigation-side-menu-item-selected-background-image);
+      background-size: var(--terra-navigation-side-menu-item-selected-background-size);
+      border-left: var(--terra-navigation-side-menu-item-selected-border-left, 0.5rem solid #007cc3);
+      color: var(--terra-navigation-side-menu-item-selected-color);
+      font-weight: var(--terra-navigation-side-menu-item-selected-font-weight, 600);
+      padding-left: var(--terra-navigation-side-menu-item-selected-padding-left, 0.7143rem);
+
+      &::before {
+        background-image: var(--terra-navigation-side-menu-item-selected-before-background-image);
+        content: '';
+        height: 100%;
+        left: 0;
+        position: absolute;
+        top: 0;
+        width: 100%;
+        z-index: -1;
+      }
 
       .chevron {
         color: var(--terra-navigation-side-menu-item-selected-chevron-color, #909496);
diff --git a/packages/terra-navigation-side-menu/src/clinical-lowlight-theme/NavigationSideMenuItem.module.scss b/packages/terra-navigation-side-menu/src/clinical-lowlight-theme/NavigationSideMenuItem.module.scss
index 9d364e62a6..125bbc414a 100644
--- a/packages/terra-navigation-side-menu/src/clinical-lowlight-theme/NavigationSideMenuItem.module.scss
+++ b/packages/terra-navigation-side-menu/src/clinical-lowlight-theme/NavigationSideMenuItem.module.scss
@@ -17,25 +17,33 @@
     --terra-navigation-side-menu-item-chevron-padding-left: 0.7143rem;
     --terra-navigation-side-menu-item-chevron-width: 0.8em;
     --terra-navigation-side-menu-item-color: #b2b5b6;
-    --terra-navigation-side-menu-item-focus-background-color: #2d3539;
+    --terra-navigation-side-menu-item-focus-background-color: #1e3a49;
     --terra-navigation-side-menu-item-focus-box-shadow: inset 0 0 0 1px #4a90e2, inset 0 0 0 4px rgba(0, 0, 0, 0.3);
     --terra-navigation-side-menu-item-font-size: 1.071rem;
     --terra-navigation-side-menu-item-font-weight: normal;
     --terra-navigation-side-menu-item-line-height: 1.42857;
     --terra-navigation-side-menu-item-focus-chevron-color: #c5c5c6;
-    --terra-navigation-side-menu-item-hover-background-color: #2d3539;
+    --terra-navigation-side-menu-item-hover-background-color: #1e3a49;
     --terra-navigation-side-menu-item-hover-chevron-color: #c5c5c6;
     --terra-navigation-side-menu-item-hover-color: #b2b5b6;
     --terra-navigation-side-menu-item-padding-bottom: 0.8225rem;
     --terra-navigation-side-menu-item-padding-left: 1.2143rem;
     --terra-navigation-side-menu-item-padding-right: 0.7143rem;
     --terra-navigation-side-menu-item-padding-top: 0.8225rem;
+    --terra-navigation-side-menu-item-selected-background-attachment: none;
     --terra-navigation-side-menu-item-selected-background-color: #004c76;
+    --terra-navigation-side-menu-item-selected-background-image: none;
+    --terra-navigation-side-menu-item-selected-before-background-image: none;
+    --terra-navigation-side-menu-item-selected-background-size: auto;
+    --terra-navigation-side-menu-item-selected-border-left: 4px solid #3496cf;
     --terra-navigation-side-menu-item-selected-chevron-color: #c5c5c6;
-    --terra-navigation-side-menu-item-selected-focus-background-color: #2d3539;
+    --terra-navigation-side-menu-item-selected-color: #b2b5b6;
+    --terra-navigation-side-menu-item-selected-focus-background-color: #1e3a49;
     --terra-navigation-side-menu-item-selected-focus-chevron-color: #c5c5c6;
     --terra-navigation-side-menu-item-selected-focus-color: #b2b5b6;
     --terra-navigation-side-menu-item-selected-hover-background-color: #1e3a49;
+    --terra-navigation-side-menu-item-selected-font-weight: 600;
+    --terra-navigation-side-menu-item-selected-padding-left: 0.7143rem;
     --terra-navigation-side-menu-item-selected-hover-chevron-color: #c5c5c6;
     --terra-navigation-side-menu-item-selected-hover-color: #b2b5b6;
     --terra-navigation-side-menu-item-text-transform: none;
diff --git a/packages/terra-navigation-side-menu/src/orion-fusion-theme/NavigationSideMenuItem.module.scss b/packages/terra-navigation-side-menu/src/orion-fusion-theme/NavigationSideMenuItem.module.scss
index 9ac6e58e65..eb83d652be 100644
--- a/packages/terra-navigation-side-menu/src/orion-fusion-theme/NavigationSideMenuItem.module.scss
+++ b/packages/terra-navigation-side-menu/src/orion-fusion-theme/NavigationSideMenuItem.module.scss
@@ -30,11 +30,19 @@
     --terra-navigation-side-menu-item-padding-left: 1.2143rem;
     --terra-navigation-side-menu-item-padding-right: 0.7143rem;
     --terra-navigation-side-menu-item-padding-top: 0.8225rem;
+    --terra-navigation-side-menu-item-selected-background-attachment: none;
     --terra-navigation-side-menu-item-selected-background-color: #e2f2fc;
+    --terra-navigation-side-menu-item-selected-background-image: none;
+    --terra-navigation-side-menu-item-selected-before-background-image: none;
+    --terra-navigation-side-menu-item-selected-background-size: auto;
+    --terra-navigation-side-menu-item-selected-border-left: 0.5rem solid #007cc3;
     --terra-navigation-side-menu-item-selected-chevron-color: #909496;
+    --terra-navigation-side-menu-item-selected-color: #1c1f21;
     --terra-navigation-side-menu-item-selected-focus-background-color: #f4f4f4;
     --terra-navigation-side-menu-item-selected-focus-chevron-color: #909496;
     --terra-navigation-side-menu-item-selected-focus-color: #1c1f21;
+    --terra-navigation-side-menu-item-selected-font-weight: 600;
+    --terra-navigation-side-menu-item-selected-padding-left: 0.7143rem;
     --terra-navigation-side-menu-item-selected-hover-background-color: #f4fafe;
     --terra-navigation-side-menu-item-selected-hover-chevron-color: #909496;
     --terra-navigation-side-menu-item-selected-hover-color: #1c1f21;