diff --git a/apps/admin-x-settings/src/components/settings/email/newsletters/NewsletterPreviewContent.tsx b/apps/admin-x-settings/src/components/settings/email/newsletters/NewsletterPreviewContent.tsx
index 650f22318e..d17c98b8d3 100644
--- a/apps/admin-x-settings/src/components/settings/email/newsletters/NewsletterPreviewContent.tsx
+++ b/apps/admin-x-settings/src/components/settings/email/newsletters/NewsletterPreviewContent.tsx
@@ -101,6 +101,18 @@ const NewsletterPreviewContent: React.FC<{
             <p className="leading-normal"><span className="font-semibold text-grey-900">To:</span> Jamie Larson jamie@example.com</p></>;
     }
 
+    let subtitleClasses = 'mb-5 text-pretty leading-[1.7] text-black';
+
+    if (titleFontCategory === 'serif' && bodyFontCategory === 'serif') {
+        subtitleClasses = clsx(subtitleClasses, 'font-serif text-[1.8rem]');
+    } else if (titleFontCategory !== 'serif' && bodyFontCategory === 'serif') {
+        subtitleClasses = clsx(subtitleClasses, 'text-[1.7rem] tracking-tight');
+    } else if (titleFontCategory === 'serif' && bodyFontCategory !== 'serif') {
+        subtitleClasses = clsx(subtitleClasses, 'font-serif text-[1.8rem]');
+    } else {
+        subtitleClasses = clsx(subtitleClasses, 'text-[1.7rem] tracking-tight');
+    }
+
     return (
         <div className="relative flex grow flex-col">
             <div className="absolute inset-0 m-5 flex items-center justify-center">
@@ -122,7 +134,7 @@ const NewsletterPreviewContent: React.FC<{
                                 <div className="py-3" style={{borderColor: secondaryBorderColor}}>
                                     {headerIcon && <img alt="" className="mx-auto mb-2 h-10 w-10" role="presentation" src={headerIcon} />}
                                     {headerTitle && <h4 className="mb-1 text-center text-[1.6rem] font-bold uppercase leading-tight tracking-tight text-grey-900" style={{color: textColor}}>{headerTitle}</h4>}
-                                    {headerSubtitle && <h5 className="mb-1 text-center text-md font-normal text-grey-700" style={{color: secondaryTextColor}}>{headerSubtitle}</h5>}
+                                    {headerSubtitle && <h5 className="mb-1 text-center text-[1.3rem] font-normal text-grey-700" style={{color: secondaryTextColor}}>{headerSubtitle}</h5>}
                                 </div>
                             )}
                             {showPostTitleSection && (
@@ -135,20 +147,17 @@ const NewsletterPreviewContent: React.FC<{
                                         Your email newsletter
                                     </h2>
                                     {(hasNewsletterSubtitle && showSubtitle) && (
-                                        <p className={clsx(
-                                            'mb-5 text-pretty text-[1.6rem] leading-[1.7] text-black',
-                                            bodyFontCategory === 'serif' && 'font-serif'
-                                        )}>A subtitle to highlight key points and engage your readers</p>
+                                        <p className={subtitleClasses}>A subtitle to highlight key points and engage your readers</p>
                                     )}
                                     <div className={clsx(
                                         'flex w-full justify-between text-center text-md leading-none text-grey-700',
-                                        titleAlignment === 'center' ? 'flex-col' : 'flex-row'
+                                        titleAlignment === 'center' ? 'flex-col gap-1' : 'flex-row'
                                     )}>
-                                        <p className="pb-1" style={{color: secondaryTextColor}}>
+                                        <p className="pb-1 text-[1.3rem]" style={{color: secondaryTextColor}}>
                                             By {authorPlaceholder}
                                             <span className="before:pl-0.5 before:pr-1 before:content-['•']">{currentDate}</span>
                                         </p>
-                                        <p className="pb-1 underline" style={{color: secondaryTextColor}}><span>View in browser</span></p>
+                                        <p className="pb-1 text-[1.3rem] underline" style={{color: secondaryTextColor}}><span>View in browser</span></p>
                                     </div>
                                 </div>
                             )}
@@ -167,8 +176,8 @@ const NewsletterPreviewContent: React.FC<{
                             )}
 
                             <div className={clsx(
-                                'max-w-[600px] border-b border-grey-200 pb-5 text-[1.6rem] leading-[1.7] text-black',
-                                bodyFontCategory === 'serif' && 'font-serif',
+                                'max-w-[600px] border-b border-grey-200 pb-5 leading-[1.7] text-black',
+                                bodyFontCategory === 'serif' ? 'font-serif text-[1.8rem]' : 'text-[1.7rem] tracking-tight',
                                 (showFeatureImage || showPostTitleSection) ? '' : 'pt-8'
                             )} style={{borderColor: secondaryBorderColor}}>
                                 <p className="mb-5" style={{color: textColor}}>This is what your content will look like when you send one of your posts as an email newsletter to your subscribers.</p>
diff --git a/ghost/email-service/lib/EmailRenderer.js b/ghost/email-service/lib/EmailRenderer.js
index b7682dc896..797a5a8ffc 100644
--- a/ghost/email-service/lib/EmailRenderer.js
+++ b/ghost/email-service/lib/EmailRenderer.js
@@ -1017,6 +1017,16 @@ class EmailRenderer {
             }
         }
 
+        let subtitleFontClass = '';
+        const bodyFont = newsletter.get('body_font_category');
+        const titleFont = newsletter.get('title_font_category');
+
+        if (titleFont === 'serif' && bodyFont === 'serif') {
+            subtitleFontClass = 'post-subtitle-serif-serif';
+        } else if (titleFont === 'serif' && bodyFont !== 'serif') {
+            subtitleFontClass = 'post-subtitle-serif-sans';
+        }
+
         const data = {
             site: {
                 title: this.#settingsCache.get('title'),
@@ -1080,7 +1090,7 @@ class EmailRenderer {
             classes: {
                 title: 'post-title' + (newsletter.get('title_font_category') === 'serif' ? ` post-title-serif` : ``) + (newsletter.get('title_alignment') === 'left' ? ` post-title-left` : ``),
                 titleLink: 'post-title-link' + (newsletter.get('title_alignment') === 'left' ? ` post-title-link-left` : ``),
-                subtitle: 'post-subtitle' + (newsletter.get('body_font_category') === 'serif' ? ` post-subtitle-serif` : ``) + (newsletter.get('title_alignment') === 'left' ? ` post-subtitle-left` : ``),
+                subtitle: 'post-subtitle' + ` ` + subtitleFontClass + (newsletter.get('title_alignment') === 'left' ? ` post-subtitle-left` : ``),
                 meta: 'post-meta' + (newsletter.get('title_alignment') === 'left' ? ` post-meta-left` : ` post-meta-center`),
                 body: newsletter.get('body_font_category') === 'sans_serif' ? `post-content-sans-serif` : `post-content`
             },
diff --git a/ghost/email-service/lib/email-templates/partials/styles-old.hbs b/ghost/email-service/lib/email-templates/partials/styles-old.hbs
index 519d1ed6ff..e8af744c1e 100644
--- a/ghost/email-service/lib/email-templates/partials/styles-old.hbs
+++ b/ghost/email-service/lib/email-templates/partials/styles-old.hbs
@@ -387,13 +387,18 @@ figure blockquote p {
     padding-bottom: 20px;
     color: #15212A;
     font-size: 17px;
-    line-height: 1.3em;
+    line-height: 1.6em;
     text-align: center;
 }
 
-.post-subtitle-serif {
+.post-subtitle-serif-serif {
+    font-family: Georgia, serif;
+    font-size: 18px;
+}
+
+.post-subtitle-serif-sans {
+    font-size: 18px;
     font-family: Georgia, serif;
-    letter-spacing: -0.01em;
 }
 
 .post-subtitle-left {
diff --git a/ghost/email-service/test/email-renderer.test.js b/ghost/email-service/test/email-renderer.test.js
index 7534d7b413..48cee5305b 100644
--- a/ghost/email-service/test/email-renderer.test.js
+++ b/ghost/email-service/test/email-renderer.test.js
@@ -2073,11 +2073,28 @@ describe('Email renderer', function () {
                 title: 'post-title post-title-serif post-title-left',
                 titleLink: 'post-title-link post-title-link-left',
                 meta: 'post-meta post-meta-left',
-                subtitle: 'post-subtitle post-subtitle-left',
+                subtitle: 'post-subtitle post-subtitle-serif-sans post-subtitle-left',
                 body: 'post-content-sans-serif'
             });
         });
 
+        it('has correct subtitle classes for serif title+body', async function () {
+            const html = '';
+            const post = createModel({
+                posts_meta: createModel({}),
+                loaded: ['posts_meta'],
+                published_at: new Date(0)
+            });
+            const newsletter = createModel({
+                title_font_category: 'serif',
+                title_alignment: 'left',
+                body_font_category: 'serif',
+                show_subtitle: true
+            });
+            const data = await emailRenderer.getTemplateData({post, newsletter, html, addPaywall: false});
+            assert.equal(data.classes.subtitle, 'post-subtitle post-subtitle-serif-serif post-subtitle-left');
+        });
+
         it('show comment CTA is enabled if labs disabled', async function () {
             labsEnabled = false;
             settings.comments_enabled = 'all';